May 2021
Beginner
306 pages
6h 20m
English
There are two classes of two-sample tests that you will see in this chapter. One is an unpaired ttest (also called a t test for independent groups) that is used to compare means between two groups. The other type of two-sample t test is a paired ttest. Commonly, a paired t test is performed when each subject is measured twice, typically before and after some treatment. It can also be used when experimental units are paired on certain characteristics such as gender and age before the experiment, and the variable of interest is the difference between values in each pair. Experimental units are often subjects, and that is the terminology subsequently used in the book.
As you saw with the one-sample t test, the two-sample ...