When to Use Which t-test?

Research Scenario and Test Choice

In my study on refusal strategies in money-related requests, I want to compare how Vietnamese participants and native speakers of American English use indirect refusal strategies. In this case, there are two groups: Vietnamese participants and American English native speakers. These groups consist of different participants, meaning the data are independent.

Since the data come from two separate groups, I would use an independent samples t-test to examine whether there is a significant difference in the mean scores of indirect refusal strategies between the two groups. This test is appropriate because it is designed to compare the means of two independent groups.

If I were instead comparing the same participants’ responses before and after a specific training session on communication strategies, I would use a paired samples t-test, as the data would come from the same individuals measured at two different times.