Overview for Paired t

Use the paired t-test to analyze the same set of items that were measured under two different conditions. You can also use to examine differences in measurements made on the same subject before and after a treatment, or examine differences between two treatments given to the same subject.

Use Paired t to do the following:

Determine whether the mean of the differences between two paired samples differs from 0 (or a target value).
Calculate a range of values that is likely to include the population mean of the differences.

For example, the manager of a fitness facility uses a paired t-test to determine whether a group of participants improved their fitness after an 8-week program. If there is a difference in fitness measurements before and after the program, the manager can use the confidence interval to determine whether the difference is practically significant.

Where to find this analysis

To perform a paired t-test, choose Stat > Basic Statistics > Paired t.

When to use an alternate analysis

If you have two samples of independent observations, use 2-Sample t instead. For more information, go to How are dependent and independent samples different?.