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ABOUT THE AP STATISTICS EXAM

HOW THE AP STATISTICS EXAM IS STRUCTURED

The AP Statistics Exam is made up of two parts: a multiple-choice section and a free response section. The entire test lasts three hours. Here’s how the time is allotted:

USING A CALCULATOR

Regarding calculators on the AP Statistics Exam, the College Board states: “Each student will be expected to bring a graphing calculator with statistical capabilities to the exam.”

Note the word expected. Although the Test Development Committee makes some effort to develop tests that can be passed without using a graphing calculator, the truth is that you will be at a disadvantage if you don’t have one. Good graphing calculators, such as the TI-83, TI-84, and TI-89 (currently the most commonly used), will not only save you time or prevent you from making minor arithmetic mistakes, but also help compute descriptive statistics such as standard deviation, correlation coefficient, and the equation of least-squares regression line. These calculators are also capable of making useful graphs, such as histograms, scatterplot graphs, and least-squares regression lines. It goes without saying that these capabilities are extremely useful on the AP Statistics Exam.

Make sure you are thoroughly familiar with the functioning capabilities of your calculator. Don’t bring an unfamiliar calculator to the AP exam. During the months before your exam, practice using your calculator until you feel confident with it.

However, you should always remember that a graphing calculator is only a computational aid. It cannot answer problems for you. Use it carefully. Interpreting numerical answers given by the calculator is still your responsibility. The calculator cannot do it for you. Nonetheless, the calculator will definitely make your computation easier, so use it.

Certain types of calculators may be prohibited from use on exams, such as calculators with QWERTY keyboards. This policy is updated as new and modified calculators enter the market. Refer to the College Board’s policy on the use of calculators on exams (it’s on the website) before purchasing one.

USING COMPUTER OUTPUTS

Due to time constraints during the exam, students are not expected to do extensive computations. For some questions, computer outputs are provided. Students are expected to make use of these outputs and interpret them correctly. Generally, only very standard, non-program specific outputs are provided. During the weeks before the exam, become familiar with the outputs of statistical programs. Learn to read them, interpret them, and use them, so you won’t be caught by surprise on the exam. When you encounter a question on the exam that comes with a computer output, be sure to read the entire question carefully before answering it, and be sure to use the given output. Do not start computing everything again. This will only waste precious time.

OVERVIEW OF CONTENT TOPICS

The curriculum for AP Statistics consists of four basic themes:

The following is an outline of the major topics covered by the AP Statistics Exam. The topics may be taught in a different order. Keep in mind that less emphasis is placed on actual arithmetic computation and more emphasis is placed on conceptual understanding and interpretation.

  1. Exploring data: observing patterns and departures from patterns (20–30%)
    1. Constructing and interpreting graphical displays of distributions of univariate data (dotplot, stemplot, histogram, cumulative frequency plot)
      1. Center and spread
      2. Clusters and gaps
      3. Outliers and other unusual features
      4. Shape
    2. Summarizing distributions of univariate data
      1. Measuring center: median, mean
      2. Measuring spread: range, interquartile range, standard deviation
      3. Measuring position: quartiles, percentiles, standardized scores (z-scores)
      4. Using boxplots
      5. The effect of changing units on summary statistics
    3. Comparing distributions of univariate data (dotplots, back-to-back stemplots, parallel boxplots)
      1. Comparing center and spread: within group, between group variation
      2. Comparing clusters and gaps
      3. Comparing outliers and other unusual features
      4. Comparing shapes
    4. Exploring bivariate data
      1. Analyzing patterns in scatterplots
      2. Correlation and linearity
      3. Least-squares regression line
      4. Residual plots, outliers, and influential points
      5. Transformations to achieve linearity: logarithmic and power transformations
    5. Exploring categorical data
      1. Frequency tables and bar charts
      2. Marginal and joint frequencies for two-way tables
      3. Conditional relative frequencies and association
  2. Sampling and experimentation: planning and conducting a study (10–15%)
    1. Overview of methods of data collection
      1. Census
      2. Sample survey
      3. Experiment
      4. Observational study
    2. Planning and conducting surveys
      1. Characteristics of a well-designed and well-conducted survey
      2. Populations, samples, and random selection
      3. Sources of bias in sampling and surveys
      4. Simple random sampling, stratified random sampling, and cluster sampling
    3. Planning and conducting experiments
      1. Characteristics of a well-designed and well-conducted experiment
      2. Treatments, control groups, experimental units, random assignments, and replication
      3. Sources of bias and confounding, including placebo effect and blinding
      4. Completely randomized design
      5. Randomized block design, including matched pairs design
    4. Generalizability of results and types of conclusions that can be drawn from observational studies, experiments, and surveys
  3. Anticipating patterns: producing models using probability theory and simulation (20–30%)
    1. Probability as relative frequency
      1. Interpreting probability, including long-run relative frequency interpretation
      2. “Law of large numbers” concept
      3. Addition rule, multiplication rule, conditional probability, and independence
      4. Discrete random variables and their probability distributions including binomial and geometric
      5. Simulation of random behavior and probability distributions
      6. Mean (expected value) and standard deviation of a random variable and linear transformation of a random variable
    2. Combining independent random variables
      1. Notion of independence versus dependence
      2. Mean and standard deviation for sums and differences of independent random variables
    3. The normal distribution
      1. Properties of the normal distribution
      2. Using tables of the normal distribution
      3. The normal distribution as a model for measurements
    4. Sampling distributions
      1. Sampling distribution of a sample proportion
      2. Sampling distribution of a sample mean
      3. Central limit theorem
      4. Sampling distribution of a difference between two independent sample proportions
      5. Sampling distribution of a difference between two independent sample means
      6. Simulation of sampling distributions
      7. t-distribution
      8. Chi-square distribution
  4. Statistical inference: estimating population parameters and testing hypotheses (30–40%)
    1. Estimation: point estimators and confidence intervals
      1. Estimating population parameters and margins of error
      2. Properties of point estimators including unbiasedness and variability
      3. Logic of confidence intervals, meaning of confidence level and confidence intervals, and properties of confidence intervals
      4. Large sample confidence interval for a proportion
      5. Confidence interval for a mean
      6. Large sample confidence interval for a difference between two proportions
      7. Confidence interval for a difference between two means (unpaired and paired)
      8. Confidence interval for the slope of a least-squares regression line
    2. Tests of significance
      1. Logic of significance testing, null and alternative hypotheses; p-values; one- and two-sided tests; concepts of type I and type II errors; concept of power
      2. Large sample test for a proportion
      3. Test for a mean
      4. Large sample test for a difference between two proportions
      5. Test for a difference between two means (unpaired and paired)
      6. Chi-square test for goodness of fit, homogeneity of proportions, and independence (one- and two-way tables)
      7. Test for the slope of a least-squares regression line

HOW AP EXAMS ARE USED

Different colleges use AP Exam scores in different ways, so it is important that you go to a particular college’s web site to determine how it uses AP Exam scores. The three items below represent the main ways in which AP Exam scores can be used:

OTHER RESOURCES

There are many resources available to help you improve your score on the AP Statistics Exam, not the least of which are your teachers. If you are taking an AP class, you may be able to get extra attention from your teacher, such as obtaining feedback on your essays. If you are not in an AP course, reach out to a teacher who teaches AP Statistics, and ask if the teacher will review your essays or otherwise help you with content.

Another wonderful resource is AP Central, the official site of the AP Exams. The scope of the information at this site is quite broad and includes:

The AP Central home page address is http://apcentral.collegeboard.com/apc/Controller.jpf.

For up-to-date information about the ongoing changes to the AP Statistics Exam Course, please visit: http://apcentral.collegeboard.com/apc/public/courses/teachers_corner/2151.html.

Finally, The Princeton Review offers tutoring and small group instruction. Our expert instructors can help you refine your strategic approach and add to your content knowledge. For more information, call 1-800-2REVIEW.

DESIGNING YOUR STUDY PLAN

As part of the Introduction, you identified some areas of potential improvement. Let’s now delve further into your performance on Test 1, with the goal of developing a study plan appropriate to your needs and time commitment.

Read the answers and explanations associated with the Multiple Choice questions (starting at this page). After you have done so, respond to the following questions:

ON THE DAY OF THE TEST

WHAT TO BRING

Pack your bag the night before the exam. Don’t forget the following:

FINALLY…

Relax. Even if all you’ve done is read this book carefully, you’re probably better prepared than a lot of the other students. Stay positive, and remember—everyone else is at least as nervous as you are.