Study design

This course is a part of Statistics and probability, a 16-course Topic series from Khan Academy.

Statistics is all about forming questions and gathering data to explore those questions. This unit covers sampling and survey methods, observational studies, and basic experiment design.

This course contains 5 segments:

Statistical questions

Statistics gives us the tools to effectively answer questions using data. So the first step in actually doing statistics is to form a question! This tutorial looks at what type of questions we deal with in statistics.

Sampling and observational studies

Taking a sample and giving a survey is one of the most common ways to get information about a large population. Doing every step well is important though, otherwise your claims may be not accurate. This tutorial covers some of the basics of samples and surveys.

Sampling methods

The goal of sampling is to get a group that is representative of its population. This lesson explores different strategies we can use — like stratified and cluster sampling — to get a good sample. We'll also look at possible sources of bias in voluntary response and convenience sampling.

Types of studies (experimental vs. observational)

This lesson covers how to distinguish between a few primary types of studies used to collect data. Learning to identify a study as either observational or experimental helps us in making appropriate conclusions.

Experiments

An experiment assigns some subjects to receive a treatment while others don't get the treatment. Experiments allow us to see how a treatment affects changes in a response variable. This lesson covers basic principles of experiment design.