Stats · Progress Checks

AP Statistics Progress Check walkthroughs.

Unit-by-unit explanations of the MCQ and FRQ content on AP Classroom Progress Checks. Each unit page shows the topics tested, the most common student mistakes, and a tip from someone who scored a 5.

Updated July 2025 Written by Mahmudul Hasan Free · No signup

9 units

All units, expandable.

Click a unit to see MCQ topics, FRQ structure, common mistakes, and a tip from a student who scored a 5.

U01Exploring One-Variable Data26 questions covered · MCQ + FRQ walkthroughs

MCQ guidance

Categorical/quantitative
Center/spread
Outliers

FRQ guidance

Boxplot interpretation

Common mistake

Confusing range and IQR.

Tip from a 5-scorer

IQR = Q3−Q1, range = max−min.

U02Exploring Two-Variable Data22 questions covered · MCQ + FRQ walkthroughs

MCQ guidance

Scatterplots
Correlation
Regression

FRQ guidance

Residual plot analysis

Common mistake

Treating correlation as causation in FRQs.

Tip from a 5-scorer

Always state “association, not causation” unless it’s a randomized experiment.

U03Collecting Data20 questions covered · MCQ + FRQ walkthroughs

MCQ guidance

Sampling methods
Experiments
Bias

FRQ guidance

Designing an experiment

Common mistake

Mixing up random sampling vs. random assignment.

Tip from a 5-scorer

Sampling = who. Assignment = which group.

U04Probability/Random Variables24 questions covered · MCQ + FRQ walkthroughs

MCQ guidance

Discrete probability
Binomial
Geometric

FRQ guidance

Binomial probability

Common mistake

Forgetting binomial conditions (BINS).

Tip from a 5-scorer

Check BINS: Binary, Independent, Number fixed, Same p.

U05Sampling Distributions22 questions covered · MCQ + FRQ walkthroughs

MCQ guidance

Mean
Proportion
CLT

FRQ guidance

Central Limit Theorem application

Common mistake

Skipping CLT check.

Tip from a 5-scorer

CLT applies when n*p ≥ 10 AND n*(1−p) ≥ 10.

U06Inference for Categorical: Proportions24 questions covered · MCQ + FRQ walkthroughs

MCQ guidance

z-test
z-interval
Chi-square GOF

FRQ guidance

One-prop z-test

Common mistake

Forgetting conditions (random, 10%, large counts).

Tip from a 5-scorer

Always state Random, 10%, Large Counts before any inference.

U07Inference for Quantitative: Means24 questions covered · MCQ + FRQ walkthroughs

MCQ guidance

t-test
t-interval
Paired

FRQ guidance

Matched-pairs t-test

Common mistake

Treating paired data as two independent samples.

Tip from a 5-scorer

Paired → use one-sample t on the differences.

U08Inference for Categorical: Chi-Square16 questions covered · MCQ + FRQ walkthroughs

MCQ guidance

GOF
Independence
Homogeneity

FRQ guidance

Chi-square independence test

Common mistake

Mixing GOF (one variable) with independence (two variables).

Tip from a 5-scorer

Two variables → independence/homogeneity. One → GOF.

U09Inference for Slopes16 questions covered · MCQ + FRQ walkthroughs

MCQ guidance

Slope test
Slope interval

FRQ guidance

Slope inference FRQ

Common mistake

Forgetting the LINER conditions for slope inference.

Tip from a 5-scorer

LINER: Linear, Independent, Normal residuals, Equal variance, Random.

Make it count

Pair the walkthrough with the calculator.

Practice loop

Do a Progress Check. Score yourself. Adjust.

After each unit, plug your AP Classroom score breakdown into the calculator. You’ll see your trajectory in real numbers, not vibes.

Open Stats calculator

Frequently asked questions

Quick answers — written by humans, not a chatbot.

What's the difference between Stats Progress Checks and the real AP exam?

Progress Checks are unscaled — they’re unit-by-unit MCQ + FRQ practice that AP Classroom assigns. The real AP exam uses a curve to map your raw composite to a 1–5. The walkthroughs above explain the reasoning; the calculator estimates your exam score.

Should I do every Progress Check or skip around?

Do them in order the first time — each one builds on the last. If you’re reviewing in May, target the units where you’re weakest using the unit summaries above.

Why don't you publish exact answer keys?

AP Classroom assignments are graded as your own work. Posting raw keys would help cheaters and harm the students using Curve for actual studying. Our walkthroughs explain reasoning, not letter answers.