A paired t-test measures whether means from a within-subjects test group vary over 2 test conditions. The paired t-test is commonly used to compare a sample group’s scores before and after an intervention. In HCI practice, the paired t-test is also commonly used to compare how a group of subjects perform in two different test conditions [12].
The paired t-test is similar to the repeated measures ANOVA test. Both can be used to compare how a static group performs in varying test conditions. The difference is that the paired t-test is used when the independent variable has two levels. Repeated measures ANOVA is used when the independent variable has more than two levels. So, for example, if the researchers had tested three conditions, the appropriate test would have been repeated measures ANOVA rather than a paired t-test