Summary AP Statistics Unit 1 Study Guide: Exploring One-Variable Data & Collecting Data (Notes for 2027 Exam)

A complete AP Statistics Unit 1 study guide for Exploring One-Variable Data and Collecting Data, written for the revised 2026–27 AP Stats course and the new May 2027 exam. These 14 full-color pages cover all 13 Unit 1 topics in the order you learn them, with clear explanations, worked examples, annotated graphs, and model answers that show exactly how to write for full credit. WHAT'S INSIDE (14 pages) • Unit 1 at a glance: every topic on one page, plus what changed in the revised course (investigative questions are new; the normal distribution and two-way tables moved to Unit 2) • All 13 topics (1.1–1.13), each on its own clearly organized page • One data set followed from start to finish, so you see how a single set of numbers becomes a dotplot, a description, summary statistics and a boxplot • Model responses to copy the style of: interpreting a categorical table, describing a distribution, comparing two distributions, and writing about bias • Step-by-step worked examples: building a boxplot, finding outlier fences with the 1.5 × IQR rule, and calculating z-scores • A Unit 1 checklist with "I can…" skills, the most common mistakes that cost points, and a one-page summary of what a study can and cannot conclude TOPICS COVERED Statistical investigative questions • individuals, variables, parameters and statistics • categorical vs. quantitative variables • relative frequency tables, bar charts, pie charts and misleading graphs • dotplots, stemplots and histograms • describing shape, center, variability and unusual features • mean, median, standard deviation, IQR, percentiles and resistance • five-number summary, boxplots and outliers • comparing distributions and z-scores • observational studies vs. experiments and confounding • simple random, stratified, cluster and systematic sampling • convenience, voluntary response, undercoverage, nonresponse and response bias, and bias vs. variability • experimental design: control, random assignment, replication, placebos, blinding, completely randomized, randomized block and matched pairs designs WHY THIS GUIDE Many AP Statistics notes still follow the old nine-unit course. This guide matches the current five-unit framework and shows what the AP exam rewards: answers written in context, complete descriptions, and the right conclusions from random sampling and random assignment. WHO IT'S FOR AP Statistics students learning Unit 1 or reviewing before a unit test or the AP exam, and teachers or tutors looking for a polished handout or review packet. Pair it with the Unit 1 Multiple-Choice Practice (100 questions with explanations) and the Unit 1 Free-Response Practice (12 FRQs with scoring guidelines), or get all three in the Unit 1 bundle. Written by Brian Cesario, PhD, a former tenured professor and experienced AP Statistics tutor. AP® is a trademark registered by the College Board, which is not affiliated with, and does not endorse, this product.