Question

If we chose to conduct a test to determine of students who study frequently, have higher GPA’s than students who do not study, would a one or two-tail test be appropriate for this scenario?

If we wanted to conduct a study to determine if people who diet lose weight much faster than people who do not diet, which type of test (one tailed or two tailed) would be appropriate for this study?

Answer 1

In the first scenario, we want to test whether students who study frequently, have higher GPA’s than students who do not study. Here, a one tailed test would be more appropriate, as a two tailed test will give results on whether the GPAs of student who do not study are different from students who study frequently, i.e , the GPA's could be higher or lower, and not just necessarily higher.

In the second scenario,we want to test whether people who diet lose weight much faster than people who do not diet. Again here, a one tailed test would be appropriate, as a two tailed test would give results based on the alternate hypothesis that people who diet lose weight differently from people who do not diet, i.e , not necessarily faster.