Sampling and Observational Studies

This lecture series discusses the studies conducted using surveys. You can use surveys to obtain information about a group of people, but it can be impossible to survey each person if the group is very large. The limited number of people surveyed is called a sample. The way a sample is selected can affect the outcome of a study and its validity. Watch the videos and complete the interactive exercises.

Practice

Types of studies - Answers

1. An experiment where the number of workouts is the response variable

The users are being randomly assigned to a treatment, so this study is an experiment. Since she is measuring the average number of workouts for those with and without the notifications, number of workouts is the response variable.

2. An observational study where religious affiliation is the explanatory variable

The people in this study weren't randomly assigned to a treatment, so this study is observational. Since they are using religious affiliation to explain lifespan, religious affiliation is the explanatory variable.

3. A prospective study

4. A sample survey