Collecting Data — AP Statistics
1. Unit at a Glance
This unit moves beyond describing existing data to teaching you how to collect data that answers the research question you want to address. We start with foundational concepts of study planning, then cover sampling methods and sources of bias before moving into experimental design and its connection to inference.
The learning arc builds incrementally: you will first learn to tell different study types apart, then master common methods for sampling and experimentation, and finally connect good data collection practices to the statistical inference you will learn later in the course. All statistical conclusions are only as reliable as the data they are built on.
Common Pitfalls
Why: These two different randomization steps serve different purposes in study design
Why: Observational studies cannot control for all confounding variables that may distort results
Why: A large biased sample is still systematically unrepresentative of the population