Question

Conduct simple effects tests of the interaction effect in Chapter 11 Exercise 1. Test to see if there are differences between the two therapies at each of the three time occasions (i.e., perform a separate test of the two therapy groups at before, week 8, and week 16). Evaluate each test at an appropriate alpha level so that the overall alpha for the three tests does not exceed .05.

Answer 1

To conduct simple effects tests of the interaction effect, compare the two therapies at each time occasion (before, week 8, and week 16). Perform separate tests for the two therapy groups at each time point and evaluate if there are any differences between the groups.

Step-by-step explanation:

To conduct simple effects tests of the interaction effect, we need to compare the two therapies at each of the three time occasions: before, week 8, and week 16. We will perform separate tests for the two therapy groups at each time point. The goal is to evaluate if there are any differences between the groups at each time occasion.

1. At the before time point, we compare the scores of the two therapy groups using an appropriate statistical test (e.g., t-test or Mann-Whitney U-test) at an alpha level such that the p-value does not exceed 0.05.
2. Similarly, for week 8 and week 16, we conduct separate tests comparing the scores of the two therapy groups using appropriate statistical tests at the same alpha level (e.g., 0.05).
3. If the p-value for any of the three tests is less than or equal to the chosen alpha level (e.g., 0.05), we reject the null hypothesis and conclude that there is a significant difference between the two therapies at that specific time occasion.