AP Statistics Study Guide

AP Statistics is less about computation and more about correctly describing what a statistical procedure shows and why it's appropriate — free-response rubrics reward precise statistical language ("we are 95% confident that...") as much as a correct number.

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Unit Breakdown

Unit 1: Exploring One-Variable Data

Describing distributions with shape, center, spread, and summary statistics.

Unit 2: Exploring Two-Variable Data

Scatterplots, correlation, and linear regression.

Unit 3: Collecting Data

Sampling methods and experimental design (a heavily-tested FRQ topic).

Unit 4: Probability, Random Variables, and Distributions

Probability rules, random variables, and the normal/binomial distributions.

Unit 5: Sampling Distributions

The Central Limit Theorem and sampling distribution behavior.

Unit 6: Inference for Categorical Data: Proportions

Confidence intervals and significance tests for one and two proportions.

Unit 7: Inference for Quantitative Data: Means

Confidence intervals and t-tests for one and two means.

Unit 8: Inference for Categorical Data: Chi-Square

Chi-square tests for goodness of fit, independence, and homogeneity.

Unit 9: Inference for Quantitative Data: Slopes

Inference for the slope of a regression line.

Unit topics reflect College Board's published Course and Exam Description at a high level — always check the current CED for exact skill weighting, since College Board revises these periodically.

Common Mistakes to Avoid

Giving a numeric answer without the required statistical justification — FRQ rubrics specifically award points for correctly stated conditions and conclusions, not just correct arithmetic.
Confusing correlation with causation, or describing an observational study's results as if it were a controlled experiment.
Mixing up when to use a t-procedure vs. a z-procedure, or which chi-square test fits a given scenario.
Writing a conclusion that overstates certainty ("this proves...") instead of the careful, conditional language statistics rubrics expect.

What's Next

Once you've worked through these units, check the AP Statistics exam format and score curve to see how MCQ and FRQ points combine into your final score, or review 2027 exam dates and registration deadlines.