Part 1 – Probability and Distribution Theory Statistical Inference and Regression Analysis: Stat-GB.3302.30, Stat-UB.0015.01 Professor William Greene Stern School of Business IOMS Department Department of Economics Part 1 – Probability and Distribution Theory Part 1 –Probability and Distribution Theory Part 1 – Probability and Distribution Theory 1 – Probability Part 1 – Probability and Distribution Theory 4/108 Sample Space Random outcomes: The result of a process Outcomes, experiments and sample spaces 800000 800000 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 Percent 900000 0 1000000 60 800000 40 Listing Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Frequency Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Listing Pie Chart of Percent vs Type Percent Mushroom and Onion 9.2% Sequence of events, Number of events, Measurement of a length of time, space, etc. 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 5/108 Consumer Choice: 4 possible ways a randomly chosen traveler might travel between Sydney and Melbourne = {Air, Train, Bus, Car} 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 6/108 Market Behavior: Fair Isaacs credit card service to major vendors = {Reject, Accept} 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 7/108 Measurement of Lifetimes A box of light bulbs states “Average life is 1500 hours” Outcome = length of time until failure (lifetime) of a randomly chosen light bulb = {lifetime | lifetime > 0} 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 8/108 Events Events are defined as Subsets of sample space, such as empty set Intersection of related events Complements such as “A” and “not A” Disjoint sets such as (train,bus),(air,car) Any subset including is a disjoint union of subsets: = (Air, Train) (Bus, Car) 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 9/108 Probability is a Measure Sausage 5.8% 900000 800000 800000 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC 900000 Scatterplot of Listing vs IncomePC Normal - 95% CI 90 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 500000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 600000 300000 100000 Probability Plot of Listing 99 700000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing Pepperoni 21.8% Percent Meatball Garlic 5.0% 2.3% Frequency Pie Chart of Percent vs Type Mushroom and Onion 9.2% Listing Percent The sample space is a - field: Contains at least one nonempty subset (event) Is closed under complementarity Is closed under countable union Probability is a measure defined on all subsets of Axioms of Probability P() = 1 A P(A) > 0 If A B = {}, P(A B) = P(A) + P(B) Listing 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 10/108 Implications of the Axioms P(~A) = 1 – P(A) as A ~A = P() = 0 as = ~ and P() = 1 A B P(A) < P(B) as B = A + (~A B) P(A B) = P(A) + P(B) – P(A B) 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 11/108 Probability Assigning probability: ‘Size’ of an event relative to size of sample space. Counting rules for equally likely discrete outcomes Using combinations and permutations to count elements Example: Discrete uniform, poker hands Example hypergeometric: the super committee (House 242R,193D, Senate 49R, 51D&I) Measurement for continuous outcomes Sausage 5.8% 900000 800000 800000 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC 900000 Scatterplot of Listing vs IncomePC Normal - 95% CI 90 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 500000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 600000 300000 100000 Probability Plot of Listing 99 700000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% Frequency Listing Percent 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 12/108 Applications: Games of Chance; Poker In a 5 card hand from a deck of 52, there are (52*51*50*49*48)/(5*4*3*2*1) different possible hands. (Order doesn’t matter). 2,598,960 possible hands. How many of these hands have 4 aces? 48 = the 4 aces plus any of the remaining 48 cards. 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 13/108 Some Poker Hands Full House – 3 of one kind, 2 of another. (Also called a “boat.”) Royal Flush – Top 5 cards in a suit Flush – 5 cards in a suit, not sequential Straight Flush – 5 sequential cards in the same suit suit Straight – 5 cards in a numerical row, not the same suit 4 of a kind – plus any other card 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 14/108 5 Card Poker Hands 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 15/108 The Dead Man’s Hand The dead man’s hand is 5 cards, 2 aces, 2 8’s and some other 5th card (Wild Bill Hickok was holding this hand when he was shot in the back and killed in 1876.) The number of hands with two aces and two 8’s is 4 4 44 = 1,584 2 2 The rest of the story claims that Hickok held all black cards (the bullets). The probability for this hand falls to only 44/2598960. (The four cards in the picture and one of the remaining 44.) Some claims have been made about the 5th card, but noone is sure – there is no record. http://en.wikipedia.org/wiki/Dead_man's_hand 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 16/108 Budget Supercommittee D 57 Senate 3 R I 41 3 2 0 How many possible committees? About 9.3E20 57(56)(55) 41(40)(39) 2(1) 3(2)(1) 3(2)(1) 2(1) 193 242 0 House 3 3 0 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 193(192)(191) 242(241)(240) 1 3(2)(1) 3(2)(1) 1 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 17/108 Conditional Probability P(A|B) = P(A,B)/P(B) = Size of A relative to a subset of Basic result p(A,B) = p(A|B) p(B) (follows from the definition) Bayes theorem Applications – mammography, drug testing, lie detector test, PSA test. 800000 800000 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 Percent 900000 0 1000000 60 800000 40 Listing Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% Frequency 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 18/108 Using Conditional Probabilities: Bayes Theorem P(A,B) P(A | B) P(B) P(B | A)P(A) P(B) P(B | A)P(A) P(A,B) P(notA,B) P(B | A)P(A) P(B | A)P(A) P(B | notA)P(notA) 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 100000 15000 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 4 5 200000 2 1 100000 15000 0 200000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 300000 10 Mean StDev N 10 500000 400000 20 300000 200000 60 50 40 30 Normal 100 12 700000 600000 70 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 80 600000 200000 369687 156865 51 0.994 0.012 Computation Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 Definition 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Theorem Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% Target 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 19/108 Drug Testing Pepperoni 21.8% Sausage 5.8% 900000 800000 800000 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC 900000 Scatterplot of Listing vs IncomePC Normal - 95% CI 90 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 500000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 600000 300000 100000 Probability Plot of Listing 99 700000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Meatball Garlic 5.0% 2.3% 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing Pie Chart of Percent vs Type Mushroom and Onion 9.2% What are P(D|+) and P(N|–)? Note, P(D|+) = the probability that a patient actually has the disease when the test says they do. Percent Frequency Listing Data P(Test correctly indicates disease)=.98 (Sensitivity) P(Test correctly indicates absence)=.95 (Specificity) P(Disease) = .005 (Fairly rare) Notation + = test indicates disease, – = indicates no disease D = presence of disease, N = absence of disease Data: P(D) = .005 (Incidence of the disease) P(+|D) = .98 (Correct detection of the disease) P(–|N) = .95 (Correct failure to detect the disease) Percent 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 20/108 More Information Deduce: Since P(+|D)=.98, we know P(–|D)=.02 because P(-|D)+P(+|D)=1 [P(–|D) is the P(False negative). Deduce: Since P(–|N)=.95, we know P(+|N)=.05 because P(-|N)+P(+|N)=1 [P(+|N) is the P(False positive). Deduce: Since P(D)=.005, P(N)=.995 because P(D)+P(N)=1. 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 21/108 Now, Use Bayes Theorem We have P(+|D)=.98. What is P(D|+)? P(D and +) P(+|D)P(D) = (By Bayes Theorem) P(+) P(+) P(+) = P(D and +) + P(N and +) P(D|+)= = P(+|D)P(D) + P(+|N)P(N) so P(D|+) = = P(+|D)P(D) P(+|D)P(D) = P(+) P(+|D)P(D) + P(+|N)P(N) .98(.005) = 0.08966 (!!) .98(.005)+.05(.995) Using the same approach, P(N|-) = 0.999889 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 22/108 Independent events Plain 32.5% 800000 800000 500000 90 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 500000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 600000 300000 100000 Scatterplot of Listing vs IncomePC Normal - 95% CI 700000 700000 600000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 900000 Percent Scatterplot of Listing vs IncomePC 900000 400000 Mushroom 16.2% Application: Infectious disease transmission Frequency Sausage 5.8% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepper and Onion 7.3% Multiplication rule P(A,B) = P(A)P(B) Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Definition: P(A|B) = P(A) Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 2 – Random Variables Part 1 – Probability and Distribution Theory 24/108 Random Variable Definition: Maps elements of the sample space to a single variable: Assigns a number to Discrete: Payoff to poker hands Continuous: Lightbulb lifetimes Mixed: Ticket sales with capacity constraints. (Censoring) 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 25/108 Market Behavior: Fair Isaacs credit card service to major vendors = {Reject, Accept} X = 0=reject, 1=accept 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 26/108 Caribbean Stud Poker {---------------- Sample Space --------------} 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 Variable 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% Probability 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 27/108 Features of Random Variables Probability Distribution Mass function: Prob(X=x)=f(x) Density function: f(x), x = ... Cumulative probabilities; CDF Prob(X < x) F(x) Quantiles: x such that F(x) = Q 900000 800000 800000 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Percent Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Frequency Pie Chart of Percent vs Type Mushroom and Onion 9.2% Median: x = median, Q = 0.5. Listing Percent 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 28/108 Discrete Random Variables Sausage 5.8% 900000 800000 800000 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC 900000 Scatterplot of Listing vs IncomePC Normal - 95% CI 90 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 500000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 600000 300000 100000 Probability Plot of Listing 99 700000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% Frequency Listing Elemental building block Bernoulli: Credit card applications Discrete uniform: Die toss Counting Rules Binomial: Family composition Hypergeometric: House/Senate Supercommittee Models Poisson: Diabetes incidence, Accidents, etc. Percent 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 29/108 Market Behavior: Fair Isaacs credit card service to major vendors X = 0=reject, 1=accept Prob(X=x)=(1-p)(1-x)px, x=0,1 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 30/108 Binomial n x n-x Prob(X=x)= p (1-p) x Sum of n Bernoulli trials 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 31/108 Examples Family has 4 children. 4 1 Prob[4 daughters] = 4 2 4 0 1 1 1 2 16 Weapons system has 20 components. It will fail if 2 or more break down. Prob any component fails is 0.2 Prob(system breaks down) = Prob[X 2] = 20 2 20 x .2 .8 x 20 x2 = 1 - Prob[X < 2] = Prob(X=0) + Prob(X=1) = (1).2 0 .820 + (20).21 .819 .819 (.8 (20).2)) .069167 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 32/108 Poisson 800000 800000 500000 400000 Mushroom 16.2% Plain 32.5% 90 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 500000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 600000 300000 100000 Scatterplot of Listing vs IncomePC Normal - 95% CI 700000 700000 600000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 Percent 900000 0 1000000 60 800000 40 Listing Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 Frequency Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepper and Onion 7.3% General model for a type of process Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Approximation to binomial Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 33/108 Poisson Approximation to Binomial n Prob(X=x|n,p)= p x (1 p) n x x 1 n n x , = np x n! = x 1 x ! n (n x)! n exp( ) x , x = 0,...,n n x! Approximation improves as 0 900000 800000 800000 600000 500000 400000 Mushroom 16.2% Plain 32.5% 90 400000 200000 100000 15000 60 50 40 30 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 Mean StDev N 369687 156865 51 80 8 4 200000 Normal 10 500000 300000 0 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 100 12 700000 400000 10 17500 Histogram of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 500000 e 1 900000 Mean StDev N AD P-Value 95 600000 x Scatterplot of Listing vs IncomePC Normal - 95% CI 99 700000 300000 100000 Probability Plot of Listing 1 n Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% n 1 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing x Percent n! x !(n x)! n np, n ,p 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 34/108 Diabetes Incidence per 1000 exp(-7)7d Prob(D=d) , d=0,1,...,1000. d! http://www.cdc.gov/diabetes/statistics/incidence/fig2.htm 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 35/108 Poisson Distribution of Disease Cases in 1000 Draws with =7 Poisson Probabilities for Diabetes Cases 0.16 0.14 PoissonProbability 0.12 0.10 0.08 0.06 0.04 0.02 0.00 800000 800000 600000 500000 400000 Mushroom 16.2% Plain 32.5% 90 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 Mean StDev N 369687 156865 51 80 8 4 200000 Normal 10 500000 300000 0 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 100 12 700000 400000 10 16 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 500000 14 Histogram of Listing 900000 Mean StDev N AD P-Value 95 600000 12 Scatterplot of Listing vs IncomePC Normal - 95% CI 99 700000 300000 100000 Probability Plot of Listing 10 17500 20000 22500 25000 IncomePC 27500 30000 32500 Percent 900000 8 Cases 0 1000000 60 800000 40 Listing Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball 6 Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% 4 Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 2 Frequency 0 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 36/108 Poisson Process: Doctor visits in the survey year by people in a sample of 27,326. = .8 Poisson probability model is a description of this process, not an approximation 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 37/108 Continuous RV Plain 32.5% 800000 800000 500000 90 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 500000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 600000 300000 100000 Scatterplot of Listing vs IncomePC Normal - 95% CI 700000 700000 600000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 900000 Percent Scatterplot of Listing vs IncomePC 900000 400000 Mushroom 16.2% Application: Lightbulb lifetimes? Frequency Sausage 5.8% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepper and Onion 7.3% Probability measure P(event) obtained using the density. Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Density function, f(x) Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 38/108 Probability Density Function; PDF Density: f(x) 0 Definition: f(x)dx=1 - Definition: CDF=Prob(X x)=F(x)= x - f(x)dx ('Cumulative Density Function' or 'Distribution Function') Probability: P(ω)= f(x)dx ω b In range a to b Prob(a < X < b) = Prob(a X b) f(x)dx a 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 39/108 CDF and Quantiles pth = quantile; 0 < p < 1 Quantile = xp such that F(xp) = p. 900000 800000 800000 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Percent Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Frequency Pie Chart of Percent vs Type Mushroom and Onion 9.2% For p = .5, xp = median Listing xp = F-1(p). Percent 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 40/108 Model for Light Bulb Lifetimes This is the exponential model for lifetimes. The model is f(time) = (1/μ) e-time/μ 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 41/108 Model for Light Bulb Lifetimes The area under the entire curve is 1.0. 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 42/108 Continuous Distribution The probability associated with an interval such as 1000 < LIFETIME < 2000 equals the area under the curve from the lower limit to the upper. A partial area will be between 0.0 and 1.0, and will produce a probability. 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 43/108 Probability of a Single Value Is Zero The probability associated with a single point, such as LIFETIME=2000, equals 0.0. 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 44/108 Probabilities via the CDF b Prob(a X b) f ( x)dx a F (b) F (a) 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 45/108 Probability for a Range of Values Based on CDF Prob(Life < 2000) (.7364) Minus Prob(Life < 1000) (.4866) Equals Prob(1000 < Life < 2000) (.2498) 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 46/108 Common Continuous RVs Continuous random variables are all models; they do not occur in nature. The model builder’s toolkit: Continuous uniform Exponential Normal Lognormal Gamma Beta Defined for specific types of outcomes 900000 800000 800000 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Percent Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Frequency Pie Chart of Percent vs Type Mushroom and Onion 9.2% Listing Percent 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 47/108 Continuous Uniform 800000 800000 500000 400000 Mushroom 16.2% Plain 32.5% 90 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 500000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 600000 300000 100000 Scatterplot of Listing vs IncomePC Normal - 95% CI 700000 700000 600000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 Percent 900000 0 1000000 60 800000 40 Listing Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 Frequency Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepper and Onion 7.3% F(x) = x/(b – a), a < x < b. Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% f(x) = 1/(b – a), a < x < b Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 48/108 Exponential f(x) = exp(-x), x > 0, 0 otherwise F(x) = 1 – exp(-x), x > 0 Median: F(M) = .5 1 – exp(-M) = .5 exp(-M) = .5 – M = ln.5 M = -ln.5/ = (ln2)/ 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 49/108 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 700000 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 49 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 50/108 Gamma Density Uses the Gamma Function Definition ( P) 0 x P 1e x dx (Note the limits of integration.) Extremely Useful Recurrence (Prove by integration by parts) ( P ) ( P 1)( P 1) Implication for positive integers: ( P) ( P 1)! and (1) 0! 1 Also useful special case: (1 / 2) 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 51/108 Gamma Distributed Random Variable P x P 1ex f ( x | , P ) , x 0, > 0, P > 0. ( P ) Used to model nonnegative random variables – e.g., survival of people and electronic components Two special cases P = 1 is the exponential distribution P = ½ and = ½ is the chi squared with one “degree of freedom” 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 52/108 Beta Uses Beta Integrals Beta density is used to model a random variable that ranges from 0 to 1 such as a proportion 1 (a, b) x a 1 (1 x)b 1 dx 0 ( a ) (b ) ( a b) ( a b) a 1 x (1 x)b 1 , ( a ) (b ) 0 x 1, a > 0, b > 0. The beta density is f(x|a,b) = Useful special case, a = 1 and b = 1 is the Uniform(0,1) 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 53/108 Normal Density – The Model 1 x -μ f(x) = exp - σ 2π 2 σ 1 2 , - < x < + Mean = μ, standard deviation = σ 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 54/108 Normal Distributions The scale and location (on the horizontal axis) depend on μ and σ. The shape of the distribution is always the same. (Bell curve) 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 55/108 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 56/108 Standard Normal Density (0,1) 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 57/108 Lognormal Distribution (ln x )2 f ( x) exp , x > 0. 2 2 x 2 1 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 58/108 Censoring and Truncation 900000 800000 800000 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Percent Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Frequency Pie Chart of Percent vs Type Mushroom and Onion 9.2% Listing Censoring Observation mechanism. Values above or below a certain value are assigned the boundary value Applications, ticket market: demand vs. sales given capacity constraints; top coded income data Truncation Observation mechanism. The relevant distribution only applies in a restricted range of the random variable Application: On site survey for recreation visits. Truncated Poisson Incidental truncation: Income is observed only for those whose wealth (not income) exceeds $100,000. Percent 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 59/108 Truncated Random Variable Untruncated variable has density f(x) Truncated variable has density f(x)/Prob(x is in range) f(x) Truncated Normal: f(x|x a)= Prob(x a) σ 1 = 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Marginal Plot of Listing vs IncomePC Normal 100 12 700000 400000 10 ,x a Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 σ σ 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 1-Φ (a-μ) Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% (x-μ) 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 60/108 Truncated Normal: f(x|x>a) = f(x)/Prob(x>a) F(x | x > XL ) 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 61/108 Truncated Poisson f(x)= exp(-) x / (x+1) f(x|x>0) = f(x)/Prob(x>0) = f(x) / [1 – Prob(x=0)] = {exp(-) x / (x+1)} / {1 - exp(-)} 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 62/108 Representations of a Continuous Random Variable Representations Density, f(x) CDF, F(x) = Prob(X < x) Survival, S(x) = Prob(X > x) = 1-F(x) Hazard function, h(x) = -dlnS(x)/dx 800000 800000 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 Percent 900000 0 1000000 60 800000 40 Listing Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Frequency Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Listing Pie Chart of Percent vs Type Mushroom and Onion 9.2% Representations are one to one – each uniquely determines the distribution of the random variable Percent 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 63/108 Application: A Memoryless Process Hazard Rate h(t ) lim t 0 Prob(t < T < t+t|T t) = Probability of failure in the next t interval given that failure has not occurred up to t. In a memoryless process, the hazard rate does not depend on how long the process has been ongoing. h(t) = (a constant) d ln S (t ) . dt General solution: S(t) = Kexp(-t) Terminal condition: S(0) = 1, so K = 1 and S(t) = exp(-t) h(t)= - F(t) = 1 - S(t) = 1 - exp(-t) = the CDF of the exponential random variable 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 64/108 A Change of Variable Theorem: x = a continuous RV with continuous density f(x). y=g(x) is a monotonic function over the range of x. y=g(x), f(y) = f(x(y)) |dx(y)/dy)| = f(x(y)) |dg-1(y)/dy)| 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 65/108 Change of Variable Applications Plain 32.5% 800000 800000 500000 90 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 500000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 600000 300000 100000 Scatterplot of Listing vs IncomePC Normal - 95% CI 700000 700000 600000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 900000 Percent Scatterplot of Listing vs IncomePC 900000 400000 Mushroom 16.2% Fundamental probability transform Frequency Sausage 5.8% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepper and Onion 7.3% Lognormal to normal Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Standardized normal Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 66/108 Standardized Normal Pie Chart of Percent vs Type Pepperoni 21.8% Sausage 5.8% 900000 800000 800000 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC 900000 Scatterplot of Listing vs IncomePC Normal - 95% CI 90 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 500000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 600000 300000 100000 Probability Plot of Listing 99 700000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Meatball Garlic 5.0% 2.3% Mushroom and Onion 9.2% 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing Percent Frequency Listing X ~ N[, 2] Prob[X < a] = F(a) Prob[X < a] = Prob[(X - )/ ] < (a - )/ y = (x - )/ J = dx(y)/dy = f(y) = f(y+ ) = [1/sqr(2)]exp(-y2/2) Only a table for the standard normal is needed. Percent 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 67/108 Textbooks Provide Tables of Areas for the Standard Normal Econometric Analysis, WHG, 2008, Appendix G, page 1093, Rice Table 2 Note that values are only given for z ranging from 0.00 to 3.99. No values are given for negative z. 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 68/108 Computing Probabilities Standard Normal Tables give probabilities when μ = 0 and σ = 1. For other cases, do we need another table? Probabilities for other cases are obtained by “standardizing.” Standardized variable is z = (x – μ)/ σ z has mean 0 and standard deviation 1 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 69/108 Standard Normal Density 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 70/108 Standard Normal Distribution Facts The random variable z runs from -∞ to +∞ (z) > 0 for all z, but for |z| > 4, it is essentially 0. The total area under the curve equals 1.0. The curve is symmetric around 0. (The normal distribution generally is symmetric around μ.) 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 71/108 Only Half the Table Is Needed The area to left of 0.0 is exactly 0.5. 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 72/108 Only Half the Table Is Needed The area left of 1.60 is exactly 0.5 plus the area between 0.0 and 1.60. 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 73/108 Areas Left of Negative Z Area left of -1.6 equals area right of +1.6. Area right of +1.6 equals 1 – area to the left of +1.6. 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 74/108 Computing Probabilities by Standardizing: Example P 4.5 x 8 | 3.5, 2.0 8 x 4.5 P 8 3.5 x 3.5 4.5 3.5 P 2.0 2.0 2.0 P[0.5 z 2.25] P[z 2.25] - P[z 0.5] 0.9878 0.6915 0.2963 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 75/108 Lognormal Distribution (lnx-μ) 2 f(x)= exp , x > 0. 2 2σ xσ 2π 1 y = lnx, x = exp(y), dx/dy = exp(y) ( y ) 2 f(y) = exp exp( y ) 2 2 exp( y ) 2 1 ( y ) 2 1 exp . 2 2 2 If x has a lognormal distribution, ln x has a normal distribution 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 76/108 Lognormal Distribution of Monthly Wages in NLS 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 700000 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 76 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 77/108 Log of Lognormal Variable 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 700000 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 77 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 78/108 Fundamental Probability Transformation x ~ f(x). F(x) is the cdf of x. What is the distribution of y = F(x), 0 y 1? The CDF of y is F(y). Prob(Y y) = Prob(F(x) y) = Prob(x F-1 (y)] = F(F-1 (y)) = y This is a uniform distribution. 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 79/108 Random Number Generation The CDF is a monotonic function of x If u = F(x), x = F-1(u) We can generate u with a computer Example: Exponential Example: Normal 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 80/108 Generating Random Samples Exponential u = F(x) = 1 – exp(-x) 1 – u = exp(-x) x = (-1/ ) ln(1 – u) Normal (,) u = (z) z = -1(u) x = z + = -1(u) + 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 81/108 U[0,1] Generation Linear congruential generator x(n) = (a x(n-1) + b)mod m Properties of RNGs Replicability – they are not RANDOM Period Randomness tests The Mersenne twister: Current state of the art (of pseudo-random number generation) 800000 800000 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 Percent 900000 0 1000000 60 800000 40 Listing Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Frequency Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Listing Pie Chart of Percent vs Type Mushroom and Onion 9.2% Percent 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 3 – Joint Distributions Part 1 – Probability and Distribution Theory 83/108 Jointly Distributed Random Variables Usually some kind of association between the variables. E.g., two different financial assets Joint cdf for two random variables F(x, y) = Prob(X < x, Y < y) 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 84/108 Probability of a Rectangle a1 b1 b2 Prob[a1 < x < b1, a2 < y < b2] y a2 x 800000 800000 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 100000 15000 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 4 5 200000 2 1 100000 15000 0 200000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 300000 10 Mean StDev N 10 500000 400000 20 300000 200000 60 50 40 30 Normal 100 12 700000 600000 70 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 80 600000 200000 369687 156865 51 0.994 0.012 F(a1,a2) Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 + 17500 20000 22500 25000 IncomePC 27500 30000 32500 Percent 900000 F(a1,b2) 0 1000000 60 800000 40 Listing Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball - Frequency Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% F(b1,a2) Listing Pie Chart of Percent vs Type Mushroom and Onion 9.2% - Percent F(b1,b2) 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 85/108 Joint Distributions Discrete: Multinomial for R kinds of success in N independent trials Continuous: Bi- and Multivariate normal Mixed: Conditional regression models 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 86/108 Multinomial Distribution N trials, X1 ,...,X N R different types of 'success' Outcome: x1 ,...,x R such that R r 1 x r =N N x1 xR Prob[X1 =x1 ,...,X R =x R ] = p ... p 1 R x ... x 1 R Example: Mix of suits in 13 card bridge hand 13! 1 Prob[XS ,X D ,X C ,X H ] XS! X D! X C! X H ! 4 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 100000 15000 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 4 5 200000 2 1 100000 15000 0 200000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 300000 10 XH Marginal Plot of Listing vs IncomePC Mean StDev N 10 500000 400000 20 300000 200000 60 50 40 30 1 4 Normal 100 12 700000 600000 70 XC Empirical CDF of Listing 14 800000 80 600000 200000 369687 156865 51 0.994 0.012 1 4 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 XD 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 1 4 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% XS 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 87/108 Probabilities: Inherited Color Blindness Inherited color blindness has different incidence rates in men and women. Women usually carry the defective gene and men usually inherit it. Pick an individual at random from the population. B=1 = has inherited color blindness, B=0, not color blind G=0 = MALE = gender, G=1, Female Marginal: P(B=1) = 2.75% Conditional:P(B=1|G=0) = 5.0% (1 in 20 men) P(B=1|G=1) = 0.5% (1 in 200 women) Joint: P(B=1 and G=0) = 2.5% P(B=1 and G=1) = 0.25% Meatball Garlic 5.0% 2.3% Pepperoni 21.8% Sausage 5.8% 900000 800000 800000 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC 900000 Scatterplot of Listing vs IncomePC Normal - 95% CI 90 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 500000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 600000 300000 100000 Probability Plot of Listing 99 700000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing Pie Chart of Percent vs Type Mushroom and Onion 9.2% Percent Frequency Listing Percent Listing 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 88/108 Marginal Distributions Prob[X=x] = y Prob[X=x,Y=y] Color Blind Plain 32.5% G=1 .4975 .0025 0.50 Total .97255 .0275 1.00 600000 500000 Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Prob[G=0]=Prob[G=0,B=0]+ Prob[G=0,B=1] Percent Scatterplot of Listing vs IncomePC 900000 400000 Mushroom 16.2% 0.50 900000 Total Frequency Sausage 5.8% .025 700000 Listing Pepper and Onion 7.3% .475 Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball B=1 Listing Pepperoni 21.8% G=0 Listing Meatball Garlic 5.0% 2.3% B=0 Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% Gender 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 89/108 Joint Continuous Distribution Probability associated with a region A Prob((X,Y) A)= A f(x,y)dydx f(x,y) is the joint density function Joint CDF For a region A = {(X,Y) with X x, Y y} F(x,y) = x y f(x,y)dydx Joint density 2 F(x,y) f(x,y) = xy 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 90/108 Marginal Distributions If f(x,y) is the joint density, x A, y B, then f(y) = A f(x,y)dx Example: f(x,y) = (x)e ( x ) y , y 0, 0 x 1. f(y) = 1 0 (λx)e-(λx)y dx. Make the change of variable to t = x 1 -ty 1 (-y)t te dt = te dt. Now let a = -y 0 0 1 at t 1 at f(y) = te dt = - 2 e 0 where a = -y 0 a a 1 f(y) = 2 2 1-λye-λy -e-λy y f(y) = 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 91/108 Two Leading Applications Copula Function - Application in Finance Bivariate Normal Distribution 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 92/108 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 93/108 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 94/108 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 95/108 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 96/108 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 97/108 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 98/108 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 99/108 The Bivariate Normal Distribution (x, y) distributed as bivariate normal if (1) Infinite range - < x,y < + (2) Normal marginal distributions: 2 2 y 1 1 x x 1 1 y f(x) = exp exp , f(y) = 2 y x 2 y 2 2 x (3) Joint Density 2 2 y y x x 1 1 x x f(x,y)= exp 2 2 2 2(1 ) 2 x y 1 x y x (6) New parameter is the correlation between x and y. 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% y y y 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 100/108 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 101/108 Independent Random Variables 800000 800000 400000 Mushroom 16.2% Plain 32.5% 90 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 500000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 600000 300000 100000 Scatterplot of Listing vs IncomePC Normal - 95% CI 700000 700000 500000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 Percent 900000 0 1000000 60 800000 40 Listing Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 600000 = 2 F(x,y)/x y = f(x) f(y) Frequency Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepper and Onion 7.3% f(x,y) Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% F(x, y) = Prob(X < x, Y < y) = Prob(X < x) Prob(Y < y) = FX(x) FY(y) Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 102/108 Independent Normals (x, y) distributed as bivariate normal x 2 y 1 1 y x f(x,y) = exp 2(1 2 ) x y 2 x y 1 2 (2) Uncorrelated; = 0 2 y y x 1 1 x f(x,y) = exp 2 x y 2 x y 2 x x 2 x y y y 1 y 2 1 x 2 1 1 y x = exp exp 2 y x 2 2 x y 2 2 In the bivariate normal case (not generally), correlation = 0 implies indepencence 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 103/108 Conditional Distributions Conditional Probability: Prob(X A | Y B) Prob(X A and Y B) = Prob(Y B) In the discrete case: Prob(X = x | Y = y) Prob(X = x and Y = y) Prob(Y = y) = Color Blind .025 0.50 G=1 (F) .4975 .0025 0.50 Total .97255 .0275 1.00 900000 800000 800000 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 Listing Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Percent Pepperoni 21.8% 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing .475 Listing Meatball Garlic 5.0% 2.3% Total G=0 (M) Pie Chart of Percent vs Type Mushroom and Onion 9.2% B=1 (Yes) Percent B=0 (No) Frequency Gender Prob(Not color blind given male) Prob(B=0|G=0) = Prob(B=0,G=0) / Prob(G=0) = .475 / .50 = .950 Prob(B=1|G=0) = .025/.5 = .05 Prob(B=1|G=0)+Prob(B=0|G=0)=1 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 104/108 Conditional Distribution Continuous Normal f (y, x) f (x) (x, y) distributed as bivariate normal f(y|x) = x 2 y 2 y y x 1 y x x f(x,y) = exp 2 2 2 2(1 ) 2 x y 1 x y x y 1 x 2 1 x f(x) = exp 2 x 2 x 2 y y [ ( / )(x )] 1 1 1 1 y y x x y|x f (y | x) exp exp 2 y|x 2 2 y|x y 2 1 2 y 1 2 1 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Marginal Plot of Listing vs IncomePC Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 2 Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 105/108 Bivariate Normal Joint distribution is bivariate normal Marginal distributions are normal Conditional distributions are normal y y|x Y x (x x ) the conditional mean function = the regression function of y on x. Note : y|x x 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 106/108 Y and Y|X Y X 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% X 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 107/108 Model Building Pepperoni 21.8% Sausage 5.8% 900000 800000 800000 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC 900000 Scatterplot of Listing vs IncomePC Normal - 95% CI 90 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 500000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 600000 300000 100000 Probability Plot of Listing 99 700000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Meatball Garlic 5.0% 2.3% 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing Pie Chart of Percent vs Type Mushroom and Onion 9.2% Percent Frequency Listing Typically f(y|x) is of interest x is generated by a separate process f(x) Joint distribution is f(y,x)=f(y|x)f(x) Ex: demographic y = log(household income|family size) x = family size y|x ~ Normal(y|x , y|x ) x ~ Poisson () Percent 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000 Part 1 – Probability and Distribution Theory 108/108 X=4 X=3 X=2 X=1 y|x ~ Normal[ 20 + 3x, 42 ], x = 1,2,3,4; Poisson 600000 500000 400000 Mushroom 16.2% Plain 32.5% Scatterplot of Listing vs IncomePC Normal - 95% CI 90 500000 400000 200000 100000 15000 60 50 40 30 17500 20000 22500 25000 IncomePC 27500 30000 32500 6 5 200000 2 1 100000 15000 400000 600000 Listing 800000 1000000 369687 156865 51 80 8 4 200000 Mean StDev N 10 500000 300000 0 Normal 100 12 700000 400000 10 Marginal Plot of Listing vs IncomePC Empirical CDF of Listing 14 800000 600000 70 20 300000 200000 369687 156865 51 0.994 0.012 80 600000 Histogram of Listing 900000 Mean StDev N AD P-Value 95 700000 300000 100000 Probability Plot of Listing 99 17500 20000 22500 25000 IncomePC 27500 30000 32500 0 1000000 60 800000 40 Listing 800000 800000 Percent 900000 Frequency Sausage 5.8% Scatterplot of Listing vs IncomePC 900000 700000 Listing Pepper and Onion 7.3% Boxplot of Listing Category Pepperoni Plain Mushroom Sausage Pepper and Onion Mushroom and Onion Garlic Meatball Listing Pepperoni 21.8% Listing Meatball Garlic 5.0% 2.3% Percent Pie Chart of Percent vs Type Mushroom and Onion 9.2% 20 600000 400000 0 0 200000 300000 400000 500000 600000 Listing 700000 800000 900000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 20 30 40 50 60 70 80 90 Listing 200000 15000 20000 25000 IncomePC 30000