Exam Format

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Statistics – 1

st

Semester Exam

Exam Will Cover:

AP Statistics

: Chapters 1.1 – 6.3

Probability and Statistics

: Chapters 1.1 – 5.5 (skip section 3.5)

Exam Format:

Both exams will consist of 30 Multiple Choice and 3 Free Response questions.

Each Multiple Choice question will be worth 2 points for a total of 60 points o Bubble Scantron sheets will be used

Each Free Response Question will be worth 10-15 points for a total of 40 points o The Free response questions will be made up of multiple parts (for example a, b, c, …)

This exam grade will count 20% toward your semester average.

You can make a single, one-sided sheet of notes to be used on the exam.

You will receive a formula sheet along with the exam of any formulas that may be necessary.

How to Prepare:

Any previous AP problem, HW problem, test or quiz problem, textbook example, or classroom example, or key definition or concept is fair game for the exam.

Use your previous tests and quizzes to find example problems

Do some select Practice Problems and Exercises from each chapter o Do the problems that match up with the concepts outlined below o There are review problems at the end of each chapter

Make sure you have read each section that will be covered. Hopefully you have already read or at least skimmed them, and you can briefly go over the highlighted terms and examples in each.

Review the example problems from each section, paying attention to the format in which they show their work.

AP Students: o Review the AP Multiple Choice practice sets that we have done. o Look at any other AP Multiple Choice set in the textbook that we have not done (at the end of each chapter) o

Review the AP Free Response questions we have done. Pay attention to the format and details in which we have repeatedly stated you need to include on these problems.

Main Concepts by Chapter:

Chapter 1: Statistical Reasoning, The Westvaco Case

Section 1.1 Exploring the Data

Dot plots and Distribution

Tables of values and Proportions or Relative Frequencies

Section 1.2 Inference

Using the dot plot to determine if the data values selected likely happened by chance or by discrimination. Use relative frequency, probability, and simple simulations. o A low probability on the simulation indicates that the situation is not likely to have happened by chance.

Correctly writing your inference in context of the problem (think like a lawyer)

Chapter 2: Exploring Distributions

Section 2.1 Visualizing Distributions: Shape, Center and Spread

Know the three key components to describing distribution: Shape, Center, Spread o Uniform, Normal, Symmetric, Skewed, Bi-Modal o Mean, Median and Mode o Range, Standard Deviation, Quartiles

Use the other components if they are present: Outliers, Gaps and Clusters

Section 2.2 Graphical Displays of Distributions

Dot Plot, Histogram, Stemplot (Stem and Leaf), and Bar Chart

Relative Frequency Histogram – know how to convert from histogram

Quantitative versus Categorical Data

Section 2.3 Measures of Center and Spread (more detail than sect. 2.1) **Very Important Section**

Mean (know the basic formula) o Know how to figure out the mean from a frequency table

Median (know how to figure it out for odd and even number data sets)

Mean vs Median placement in a skewed data set (ie: which is shifted further out)

Know what to use for which types of distribution

5-Number Summary for data set (min, Q1, median, Q2, max): know how to find by hand and with calculator

IQR

Determining Outliers: 1.5 times IQR more than the nearest quartile

Box-Plots

Standard Deviation Formula (don’t need to memorize, but do need to understand meaning) o What is the SD basically telling you o Why do we square the deviations from zero (x-xbar) o Know how to figure out the SD from a frequency table using your calculator

Using 1-Var Stats: know what info is on this screen

Section 2.4 Working with Summary Statistics

Mean, Median, SD, IQR, 5-Number Summary

Know when to use which measures for certain types of distributions

Influence of Outliers on the Summary Stats

Recentering a data set

Rescaling a data set

Percentiles (know the definition)

Cumulative Frequency Plots o Be able to convert Frequency, Relative Frequency and Cumulative Frequency Plots

Section 2.5 Normal Distribution **Very Important Section**

Know the basic shape and characteristics of a normal distribution

Know what a “standard normal distribution” is o Mean of 0, SD of 1 o Z-Scores are the # of SDs from the mean

Finding z-scores given mean, SD and a data value

Using z-scores to find percentages within the normal curve o Using z-table and using normalcdf

Using a given percentage to find z-scores o Using z-table and invNorm

Given a z-score find the actual raw data value

Know the central interval percentages vs SDs for a Normal Curve

Chapter 3: Relationships Between Two Quantitative Variables

Section 3.1 Scatterplots

Understanding the relation a scatterplot shows (Independent variable on the x-axis and

Dependent on y-axis)

Describing the pattern: o Identify variables and cases o Describe the shape: linear or curved, clusters and outliers o Describe the trend: positive or negative o Describe the strength of the relationship: Strong, Medium or Weak; or Varies

Understand the idea of generalizing a pattern to other cases

Explanations for the relation

Lurking Variables that could cause the relation

Section 3.2 Creating a Line to Fit the Pattern

Know specifically what slope of the line means in context of the problem. o “the change in the response for every additional unit in explanatory variable

Know what the y-intercept means in context of the problem o The value of the response when the explanatory is zero

Using the line of best fit, regression line, least squares line (all synonyms) as a predictor

Know the details of Residuals

Sum of Squared Errors: just know in general what it tells you

Knowing how to use linreg(a+bx) on calculator

Properties of least squares regression line p.125

Reading computer printout of linear regression o Variable, coefficient, R Squared,

Section 3.3 Correlation: The Strength of a Linear Trend

Correlation = r o r is equal to or between -1 and 1 o The closer to -1 or 1, the closer the points are to the least squares line and the stronger the correlation o Negative r relates to a negative slope, positive r relates to a positive slope

Know how to use the formula for calculating r based on z-scores for x and y values. o Know how the characteristics of the Zs affect r

Comparing r with the shape of the data and analyzing appropriateness of the fit of the line. o Strong r doesn’t necessarily mean a good fit (it could be curved)

Know how to use formula for slope of the line along with r and the SDs for x and y values p.146

Correlation does not imply Causation (possible lurking variables)

Coefficient of Determination, r 2 : know its meaning specifically o The proportion of the variation in the response that is due to the linear relation with the explanatory variable.

Section 3.4 Diagnostics: Looking for Features That the Summaries Miss

Potentially Influential Points: do they change the slope or y-intercept o Points further out in the x direction tend to have more influence on slope o Points way above the line, but directly above the x mean don’t have much effect on the slope

Residual Plots: Know how to create and read them o The more scattered without a pattern indicates a decent fit by the line. o The more a pattern shows up, the more it indicates there is a curve to the data.

Section 3.5 Shape Changing Transformations **Regular Probability and Statistics can skip this section**

Exponential Growth or Decay can be linearized by doing a log (of y) transformation

Power functions can be linearized by doing a log-log (of both y and x) transformation

Simply be able to understand transformations that have been done and answer questions based on what has been done for you. o For example: Is the new data linear or still curved? Which transformation is a better fit? Find the value of y when x is __ with the transformed equation.

Chapter 4: Sample Surveys and Experiments

Section 4.1 Why take Samples and How Not To

Census vs a Sample

Advantages of a Sample

What is the Population and what is a Unit

What is a Parameter

Bias of a Sampling Method: Know the types of sampling bias o Voluntary response, size, convenience, nonresponse, questionnaire, incorrect response

Section 4.2 Methods of Random Sampling

Simple Random Sample (SRS) o Know methods of selecting a truly random sample o Numbering a list and using random table of generator to select

Stratified Random Sample o Know that stratifying can improve accuracy of sample

Cluster Sample

Two-Stage Cluster Sample

Systematic Sample

Section 4.3 Experiments and Inference About Cause

Be careful about making statements of Cause and Effect - because of lurking variables

Two influences on an outcome are confounded if they are mixed in a way that their effects cannot be separated.

Know what a treatment is

Know how an observational study differs from an experiment

Importance of Randomizing

Using a control or comparison group is critical

Placebos

Blind and Double Blind

Experimental Units and Replication

Characteristics of a Well-Designed Experiment o Compare two or more groups o Randomize o Replicate

4.4 Designing Experiments to Reduce Variability

Understand: Differences between Treatment Groups and Variability within Treatments

Why do you want to control variability within treatments? o It is easier to see differences between treatments so your experiment can tell you something. o The difference between treatments must be large enough to overshadow the variation within treatment.

Completely Randomized Design (CRD)

Randomized Paired Comparison (Matched Pairs: match up based on similar ability or some other characteristic. Then randomly assign different treatments to each)

Randomized Paired Comparison (Repeated Measures: Use the same unit and apply each treatment to it)

Randomized Block Design o Block for variation you know about (Block similar thing together) o Randomize for variation you don’t know about

Chapter 5: Probability

Section 5.1 Constructing Models of Random Behavior

Definition of Probability

What an Event is

What a Sample Space is

Law of Large Numbers

Fundamental Principle of Counting

Section 5.2 Using Simulation to Estimate Probabilities

Steps in a Simulation o State your assumptions about the proportions in real life o Describe how the numbers of your model and random selection of them simulate real life o Repetition of the simulation a large number of times. o Write the conclusion of the simulation in context of the problem

Know how to use a random number table or generator on calculator to select numbers that represent random selection of something in real life

Section 5.3 Addition Rule (OR Problems)

Know how and when to use addition formula P(A or B) = P(A)+P(B)-P(A and B)

Know what disjoint (mutually exclusive) means and when it applies or does not apply

Know how to use or create a two-way table to solve problems

May want to know how to use Venn Diagrams (not necessary, but could be helpful)

Section 5.4 Conditional Probability and the Multiplication Rule (AND Problems)

Conditional Probability from a two-way table

Know how and when to use Multiplication formula o P(A and B)=P(A)*P(B|A) or P(A and B)=P(B)*P(A|B) o They are equivalent

Know how to apply the Conditional Probability Formula p.330

Section 5.5 Independent Events

Definition of Independent Events: P(A) and P(B) > 0, Then A and B are independent if and only if

P(A|B) = P(A), or equivalently P(B|A) = P(B).

Then P(A and B) = P(A)* P(B)

Know how to use the above to show events are independent or calculate the probability of combined independent events.

Know “Total Probability” which uses “OR” & “AND” along with conditional probability on a 2way table to figure out the total probability of a given situation.

Section 6.1 Probability Distributions

Know how to create a distribution for a situation (especially when probability is not 50%)

Expected value is the mean of the distribution 1 VAR STAT L1,L2 (weighted average like semester grade)

Can find the standard deviation from 1 VAR STAT L1,L2 also

Recentering, Rescaling of distribution rules

Combining 2 or more distribution rules.

Section 6.2 Binomial Distributions

Know the characteristics of a Binomial Distribution o Looking for a certain number of successes out of a total o There are only two possibilities for each trial (success or failure) o A fixed total number of trials o Each trial independent o Probability of success stays the same

Expected value = np

Standard deviation = sqroot of (np(1-p))

Section 6.3 Geometric Distributions

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