The paired t-test is useful for analyzing the same set of items that were measured under two different conditions, differences in measurements made on the same subject before and after a treatment, or differences between two treatments given to the same subject.
For example, a manager at a fitness facility wants to determine whether a weight-loss program is effective. Before collecting the data for a paired t-test, the manager uses a power and sample size calculation to determine the effect of varying sample sizes on the power function of the test.
To perform a power and sample size calculation for a paired t-test, choose.
If the observations in your sample are independent and are not matched samples, use Power and Sample Size for 2-Sample t instead. For more information, go to How are dependent and independent samples different?.