About 16% of AP Statistics students score a 5. The FRQ section (5 short questions + 1 investigative task = 40% of score) is where most scores diverge. Students who score 3s know the formulas. Students who score 5s know how to write conclusions in context and state conditions correctly every time.
Score Breakdown
- Multiple Choice (60%): 40 questions in 90 minutes — no penalty for guessing
- FRQ Short (30%): 5 problems, ~75 minutes — test specific procedures
- Investigative Task (10%): 1 multi-part problem, ~25 minutes — connects multiple concepts
Mastering Inference — Where Most Points Are Won or Lost
Inference procedures (Units 6–9) account for 35–45% of the exam. For every test or confidence interval, the structure is: STATE → PLAN → DO → CONCLUDE.
- STATE: Define your parameter in words. "Let p = the true proportion of adults who..." Identify the hypotheses if testing.
- PLAN: Name the procedure and verify conditions (Random, Normal/Large Sample, Independent 10% condition).
- DO: Calculate the test statistic and p-value (or the interval bounds). Show formula and plug-in.
- CONCLUDE: Interpret in context. "Because p-value = 0.03 < α = 0.05, we reject H₀. We have convincing evidence that the true proportion of [context] is greater than [claimed value]."
Priority Units
- Units 4–5 (Probability): Know binomial distribution (np≥10, n(1-p)≥10 for Normal approximation), Central Limit Theorem, and how to calculate P(X̄ < k) using z-scores.
- Unit 6 (Inference for Proportions): One-proportion z-test and z-interval — the most frequently tested procedure. Know both and practice the CONCLUDE step in context.
- Unit 7 (Inference for Means): One-sample t-test, paired t-test, two-sample t-test. Conditions differ slightly — know the differences.
- Unit 9 (Chi-Square Tests): Three chi-square tests (goodness of fit, independence, homogeneity) — know which to use and how to state the conclusion.
The Investigative Task Strategy
Read all parts before starting — they build on each other. Budget 25 minutes. If part (c) requires output from part (b), complete part (b) first even if part (a) is unclear. Each part is scored independently — a wrong part (b) doesn't prevent you from earning points in parts (c) and (d) if your reasoning is consistent.
Writing Conclusions That Score
The most common point-loss in FRQs is an incomplete conclusion. "Reject H₀" scores 0. "We have sufficient statistical evidence at the α=0.05 level that the mean [measured quantity] differs from [claimed value] for [population]" scores full credit. Practice writing one complete conclusion every time you work an inference problem.
AP Statistics Practice Questions · AP Stats Study Guide · AP Stats Practice Test
AP and Advanced Placement are trademarks of College Board. AimFive is not affiliated with or endorsed by College Board.
