Math 12/ Advanced Math 12 Probability Unit Time frame: 10%-15% of total course time is suggested by the Department of Education. 1 We recommend 2 - 2 weeks at the beginning of the semester. Then include this topic 2 in the cumulative testing. Suggestions: Topic Definition of probability Fundamental Counting Principle Suggestions Focus A (pp.300-302) Emphasize definition of probability, complement ( A is the complement of A ), experimental vs. theoretical probability *Some teachers do the Venn Diagrams before this principle. Inv.3 (pp.307-309) Explain tree diagrams. Emphasize: “and” indicates multiplication Venn Diagrams Inv.5 (not mutually exclusive) Inv.6 (mutually exclusive) Emphasize: “and” indicates intersection ”or” indicates union Recommended questions #’s 3,4(omit 4e), 5,6,10,11 p.318, #43 See supplementary Questions. Page 308 #’s 3-7 Page 321 #49,50 See supplementary Questions. Pages 312-315 #’s 21-36 Omit #35 at this time. See supplementary Questions. Page 301 # 4(e) P(AorB)=P(A)+P(B)-P(A and B) P(A and B)= P(A B) For mutually exclusive events, P(A and B)=0 (no intersection) P(AorB)=P(A)+P(B) Arrays An array (table) is a useful way to explore the possible sums when tossing two dice. Factorial Notation Focus F (pp.329-331) Combinations/Permutations Inv.10 (pp.327-328) to emphasize the distinction between combinations and permutations. Page 315 # 35 #’s 8-14, omit #12 p.328,#’s1,2 See supplementary Questions. Permutations Special Permutations Combinations Emphasize methods of calculating permutations: 1) list all possible outcomes 2) fundamental counting principle 3) formula How do we know when to use permutations? -indication of order or position Ex: -1st, 2nd, 3rd, - President., Vice Pres., Treasurer - arrangements 1) circular (n-1)! Ex.: How many ways can eight people be arranged around a circular table? 2) Repetitions within permutations Ex.: How many permutations are there using the letters in the word bubbles? When do we use combinations? -indication that order, position not important Ex. Anonymous groups, committees Applying Section 5.4, Focus H page 336 Combinations/Permutations Emphasize nature of the question: to Probability “How many ways…?” (not a probability question; requires a whole number answer) vs. “What is the probability that…?” (requires a rational number answer between 0 and 1). Conditional Probability Focus E, Investigation 8 (Advanced only) Emphasize , as in Venn Diagrams, “and” in Conditional Probability is intersection Recall A is the complement of A. Page 332 #16,17,18a,19 See supplementary Questions. Page 332 #18b,20 See supplementary Questions. Page 333 #21-34 See supplementary Questions. Page337 #2-16 Page 310 #10,11,12 Page 324 # 58,59,60 See supplementary Questions. Page 320 #47,48 Page 322 Procedure A,B,C Omit: Investigation 1 page 303, Investigation 2page 304, Focus D, Investigation 7, Sections 5.5,5.6 Caution: Many students have difficulty in probability problems involving the words “or” and “and”. It is important to make clear the use of “or” in English language in comparison to its use in Mathematics. “Or” in English refers to either/or. “Or” in Mathematics includes the possibility of both. In Venn Diagrams and Conditional Probability, “and” implies intersection. In other situations, “and” implies multiplication (according to the Fundamental Counting Principle). An extension of this principle is P(A and B)= P(A) x P(B). Students should be using the Study Guide from the Department of Education Websites Nova Scotia Department of Education http://itembank.ednet.ns.ca Newfoundland Dept. of Education http://www.ed.gov.nl.ca/edu/k12/pub/sample.htm Yearly timeline 2005-2006 used by Elaine MacEachern, GBHS First semester Sept.9-Sept.26: Probability Chapter5 Sept.27-Oct.27: Circles Chapter 4 Oct.31-Dec.6: Quadratics Chapter 1 Dec.7-Dec.16; Jan.3-Jan.24: Exponential Growth Second semester Feb.8-Feb.23: Probability Feb.24-March28: Circles March29-May4: Quadratics May5-June12: Exponential Growth Questions from Nova Scotia Provincial Mathematics Examinations 1) Two coins and one die are simultaneously tossed on a table. What is the probability of obtaining two heads and a six? a) 5 / 12 (b) 1/ 24 (c) 1/ 5 (d) 1/ 8 2) If we shuffle a standard deck of 52 cards and randomly select one card, what is the probability of selecting a king or a queen? a) 1/ 52 (b) 1/ 26 (c) 1/ 13 (d) 2/ 13 3) Two boxes contain marbles. The first contains five red marbles and three white marbles. The second box contains four black marbles and seven green marbles. One marble is chosen at random from each box. What is the probability that a white and a black marble will be chosen? a) 3/ 22 (b) 33/ 32 (c) 1/ 12 (d) 12/ 35 4) Tim and Rebecca are the first and second students in a line of 7 students waiting to buy tickets for a concert. The number of different orders in which the remainder of the students can line up behind them is 7! a) 5! (b) 7! (c) (5!)(2!) (d) 2! 5) Use a real-life example to explain why 4 C4 1 . 6) A fair coin is tossed three times. Draw a tree diagram and determine the probability of obtaining a) no heads b) exactly 2 heads c) at least one head 7) A class is made up of 13 girls and 9 boys. If 5 students are chosen at random, what is the probability that 5 girls will be chosen? 8) A bag contains x red beads, y yellow beads and z blue beads. Two beads are drawn at random, with the first being replaced before the second is drawn. What is the probability (in terms of x, y and z) that both beads are red? 2x x2 x 2x a) (b) (c) (d) 2 ( x y z) 2 x yz x yz ( x y z) 9) A class is made up of 13 girls and 9 boys. What is the probability that, of 5 students chosen at random, 3 are girls and 2 are boys? 10) While working on a problem, Christine observed that 5 P1 and 5 C1 gives the same value, but that the value for 5 P2 is larger than the value for 5 C 2 . Why is this so? 11) Mr. Smith has 3 pairs of black pants and 2 pairs of grey pants in the first drawer of his dresser. In the second drawer, he has 1 white shirt and 4 multi-colored shirts. He gets up late one morning and without looking quickly grabs a pair of pants from the first drawer and a shirt from the second drawer. What is the probability that he grabs a pair of black pants and a white shirt? a) 3 25 (b) 4 25 (c) 4 5 (d) 2 5 12) Based on the information in the table below, the probability that a person did not take vitamins regularly given that this person developed a cold is Developed a cold Took vitamins regularly Did not take vitamins regularly Total a) 115 352 (b) 115 167 Did not develop a cold Total 46 139 185 115 52 167 161 191 352 (c) 46 352 (d) 115 161 13) Empire Theatres observed 25 movie goers. Of them, 15 ordered a drink, 8 ordered popcorn and 5 ordered both. a) Display the results in a Venn Diagram. b) Based on your diagram, what is the probability that a movie-goer will buy popcorn, given that the person buys a drink? 14) Use the following chart to calculate the probability of being a blonde, given you are male, Blonde Not Blonde Male 15 18 Female 8 12 15) Peter, Mary and Susan are part of a group of 10 people. An executive consisting of Peter as the President, Mary as the Treasurer, and Susan as the Secretary could be formed from this group. What is the probability this executive will be formed? 1 1 3! 3 a) (b) (c) (d) P 10 P3 10 C 3 10 C 3 10 3 16) Number of students Applied for a summer job 120 Number of students got an interview 100 Number of students got a summer job 75 Number of students did not get an interview 20 Number of students did not get a summer job 25 What is P( student got a summer job / student got an interview) ? 1 a) 5 (b) 3 (c) 5 (d) 8 4 6 3 17) You want to put 8 different books on a shelf, side by side. In how many ways can these books be arranged? 8! a) 8! b) c) 8 P1 d) 8 C 8 2! 1000! is: 999! (b) 1.001 (c) 1000 18) The value of a) 1 (d) undefined 19) A Prom Committee of 7 will be chosen from 10 boys and 12 girls. Calculate the probability that exactly 5 girls will be chosen to be on the committee. 20) Use a real-life example to explain why 5 C 2 5 C3 . 21) At a high school, the following data was obtained indicating students enrolled in grade 12 math. Sex Advanced Math 12 Math 12 Total Male 63 85 148 Female 72 112 184 Total 135 197 332 Assume that event A is “enrolled in Advanced Math 12” and event B is “male”. (a) P(A) (b) P(B/A) 22) If an event can succeed in “s” ways and fail in “f” ways, then the probability of success is: s s a) (b) (c) ( s)( f ) (d) 1 f f f s 23) Two dice are thrown. Given that the sum of the two numbers on the pair of dice is greater than 7, what is the probability that these two numbers are the same? 1 5 1 1 a) (b) (c) (d) 5 12 12 2 24) In a school of 200 students, 80 have blood type O. If 5 students are chosen at random, what is the probability of selecting five students with type O blood? 1 1 1 1 1 x x x x a) 80 79 78 77 76 5 b) 80 C 5 5 c) 80 P5 C d) 80 5 200 C 5 25) Refer to the following chart Event A 10 15 Event B Event B Event A 20 25 Calculate a) P(A or B) b) P(A/B) 26) From a group of 5 men and 6 women, what is the probability that a committee formed at random will consist of 3 men and 3 women? 27) Joe, Mary and George are among the seven finalists for a random draw to win three different prizes. What is the probability that Joe will win 1st prize, Mary will win 2nd prize, and George will win 3rd prize? Express your answer in fraction form. 28) John, Amy and Fred tried to solve the following problem: In a certain city, during a person’s lifetime the probability of having diabetes is 0.10 and the probability of having cancer is 0.05. What is the probability of a person’s having either diabetes or cancer in his/her lifetime? Suppose that event C is “person having cancer” and event D is “person having diabetes”. Their proposed solutions are as follows: John’s solution: P(C and D)= (0.10)(0.05)=0.005 Amy’s solution: P(C or D) = 0.10+0.05=0.15 Fred’s solution: P(C or D) = 0.10+0.05-0.005 + 0.145 a) Which student has the correct answer? b) Explain why the other two solutions are NOT correct. 500! is 499! (b) 1.002 (c) 500 29) The value of a) 1 (d) undefined 30) Consider the following Venn diagram Event K Event L Which of the following is correct? a) P(K or L) = P(K) + P(L) b) P(K and L) = P(K) + P(L) c) P(K or L) = P(K) x P(L) d) P(K and L) = P(K) x P(L) 30) Your math teacher gives your class a list of eight questions to study. Five of the eight questions will be randomly selected for the next test. If you study only the first five questions from the list, the probability that all of those five questions will be on the test is: 1 1 5 1 a) (b) (c) (d) 8 8 8 C5 8 P5 31) There are 5 red marbles and 7 blue marbles in a bag. Two marbles are chosen randomly without replacement. The probability that a red and then a blue marble will be chosen is: 1 1 5 7 5 7 a) x (b) (c) (d) 12 11 12 11 5 C1 x 7 C1 12 C 2 32) There are 15 jellybeans distributed in a jar: 5 are yellow and 10 are orange. You reach into the jar and, without looking, remove 2 jellybeans. What is the probability that you will remove 2 yellow jellybeans? 33) In a group of 15 people, 4 are left-handed and 11 are right-handed. Seven people are selected at random from this group. (a) What is the probability that all 4 left-handed people will be selected? (b) If Sarah and Mike, two of the left-handers, have already been chosen, what is the probability that all the other members selected will be right handed? 34) Create a real-life problem that demonstrates P(A or B) = P(A) + P(B) – P(A and B) when the events A and B are NOT mutually exclusive. (You do not have to solve the problem) Teacher Resource Probability Unit Mathematics 12/ Advanced Mathematics 12 Contributors: Arlene Andrecyk Elaine MacEachern Sandy Urquhart Cape Breton-Victoria Regional School Board January 2007.