College · Aligned to AP Statistics
Introduction to Statistics (STAT 101) — study guide & practice questions
Describing data, regression, sampling and experiments, probability, and inference with intervals and tests: full AP Statistics scope.
Study guide
Describing Data
- Describe distributions by shape, outliers, center and spread, in context.
- r measures linear association only; correlation is not causation.
Collecting Data
- Random assignment supports cause and effect; random selection supports generalization.
- A larger sample reduces variability but never fixes bias.
Inference
- Confidence interval = statistic ± critical value × standard error.
- If the p-value < α, reject H₀; otherwise fail to reject it.
Course modules
4 foundation modules free to read here; 3 AP-level and advanced modules with Pro. Every module ends with a quiz in the app.
1. Exploring One-Variable Data Free
Types of variables, describing distributions by shape, center and spread, outliers, and z-scores.
Read the 3 lessons →2. The Normal Model & Linear Regression Free
The empirical rule and normal calculations, correlation, least-squares regression lines, residuals, and r².
Read the 3 lessons →3. Collecting Data: Sampling & Experiments Free
Sampling methods and bias, observational studies vs. experiments, and the principles of experimental design.
Read the 3 lessons →4. Probability & Random Variables Free
Probability rules, conditional probability and independence, expected value, and binomial distributions.
Read the 3 lessons →5. AP: Sampling Distributions Pro · AP Stats · Unit 5
How statistics vary from sample to sample, the sampling distributions of p̂ and x̄, and the Central Limit Theorem.
6. AP: Confidence Intervals Pro · AP Stats · Units 6–7
Building and interpreting confidence intervals for proportions and means, conditions, and what affects the margin of error.
7. AP: Significance Tests Pro · AP Stats · Units 6–9
Hypotheses, test statistics and p-values, conclusions in context, Type I and II errors, power, and choosing the right test.
Sample practice questions
From module 1, Exploring One-Variable Data. Pick your answers, then check them in the app, with an explanation for every question.
1. Q1 = 12 and Q3 = 18. The lower outlier fence is:
2. A value has z = −2. It is:
Sample flashcards
4 of the cards in this course's deck. Tap a card to flip it.
Exploring DataThe 1.5 × IQR outlier rule
A value is an outlier if it is below Q1 − 1.5·IQR or above Q3 + 1.5·IQR.
Exploring Dataz-score formula
z = (x − mean) / SD: how many standard deviations a value lies from the mean.
Normal ModelThe empirical rule
About 68%, 95% and 99.7% of a normal distribution fall within 1, 2 and 3 SDs of the mean.
RegressionResidual
Observed y − predicted ŷ. A negative residual means the model overpredicted.
The full course is in LectureMate's Course Library: every module quiz with explanations, the complete flashcard deck with spaced repetition, and a 6-step strategy for AP Statistics questions. Foundation modules are free; AP-level and advanced modules need Pro.