AP® Statistics

Flashcards

158 cards with the terms and ideas you need to know cold. The ones you find hard come back sooner.

Multiple choice practice

285 exam-style questions, timed like the real exam, with every answer explained.

Practice exam

The whole multiple choice section: 42 questions in 1 hour 30 minutes, weighted by unit like the real exam. A fresh mix every time.

Must-know sheet

The facts, rules and terms to know cold on exam day, on one page. Filter it by unit, or print it.

Free-response practice

24 free-response questions like the ones on the exam. Score your answer with the rubric and a model answer, or sign in for free AI scoring.

Exploring One-Variable Data and Collecting Data

13 topics · 78 videos

• A good investigative question names the variable, the population and what you want to find out
• Describe a distribution's shape, center, variability and unusual features, always in context
• The median and IQR resist outliers; the mean, standard deviation and range don't
• Random sampling is what lets you generalize from a sample to a population
• Random assignment in an experiment is what allows cause-and-effect conclusions

Probability, Random Variables, and Probability Distributions

12 topics · 72 videos

• Two categorical variables are associated when the conditional distributions differ
• A probability is the long-run relative frequency of an outcome
• Conditional probability shrinks the sample space to what you already know happened
• A random variable's mean and standard deviation summarize its distribution
• Statistics vary from sample to sample, and a sampling distribution shows how much

Inference for Categorical Data: Proportions

15 topics · 86 videos

• A sample proportion p̂ is used to estimate the population proportion p
• Before any inference, check the conditions: randomization, 10% and normality (expected counts for chi-square)
• A confidence interval gives a range of plausible values for a parameter
• A small p-value means your result would be surprising if the null hypothesis were true
• Every test risks a Type I or a Type II error, and power is the chance of catching a real effect

Inference for Quantitative Data: Means

10 topics · 57 videos

• Sample means vary less than single values: their standard deviation is σ/√n
• When σ is unknown, use s with t* and t-tests
• Paired data turn into one sample of differences
• Check randomization, the 10% condition, and n ≥ 30 or a sample with no strong skew or outliers
• Intervals and tests for means follow the same logic as for proportions

Regression Analysis

5 topics · 32 videos

• Describe a scatterplot by its form, direction, strength and unusual features
• Correlation r measures only linear strength and direction, and it isn't causation
• The least-squares line makes the sum of squared residuals as small as possible
• A residual plot with no pattern supports using a linear model
• Interpret the slope, the y-intercept and r² in context