AP Statistics Unit 8 Progress Check Inference for Categorical Data: Chi-Square walkthrough.
AP Statistics Unit 8 is chi-square inference, and the Unit 8 Progress Check MCQ tests whether you can pick the right one of three chi-square tests and check its conditions. This walkthrough covers what the questions ask, the traps, and how to reason through them. Explanations only — no AP Classroom answer keys.
What Unit 8 covers
Unit 8 is Inference for Categorical Data: Chi-Square. Inference: chi-square is roughly 2–5% of the AP Statistics exam but a common free-response topic.
The Progress Check MCQ: what each question type tests
These are the question patterns that recur on this Progress Check, and what each one is really asking.
The Progress Check FRQ
Unit 8 free response gives a table and asks you to run the appropriate chi-square test. Points come from choosing the right test, computing expected counts, checking that all are at least 5, calculating the statistic and degrees of freedom, and stating a conclusion in context linked to the P-value.
Where students lose the most points
How to work through this unit
Before any chi-square question, decide the test from how the data were collected: one sample and one variable, one sample and two variables, or several samples. The design picks the test.
Once you have finished the Progress Check, put your raw score into our AP Statistics Calculator to see roughly where that pace puts you on the 1–5 scale, and use the AP Statistics Review for the full exam format and study plan.
Frequently asked questions
Quick answers — written by humans, not a chatbot.
What does the AP Statistics Unit 8 Progress Check cover?
Chi-square inference: the chi-square statistic, the goodness-of-fit test, the test for independence, the test for homogeneity, expected counts, and degrees of freedom.
How do I choose between the three chi-square tests?
By the study design. One variable compared to a model is goodness-of-fit, two variables from one sample is a test for independence, and one variable compared across several samples is a test for homogeneity.
What is the condition for a chi-square test?
All expected counts must be at least 5, along with the random and independence conditions. The condition is about expected counts, not observed counts.
Do you publish AP Statistics Unit 8 answer keys?
No. We publish walkthroughs of the reasoning and traps rather than AP Classroom answers.