I am really hoping you can shed some light on a topic that I am struggling with.
I have a 2x3x4 repeated measured anova. I have a significant 3-way interaction, and I want to make sure that I am using the correct post hoc comparisons and not violating any key statistics theory.
If we consider my 2x3x4 RM ANOVA to be AxBxC. With the significant 3-way interaction I have performed the following post-hoc analysis:
AxB at each level of C
AxC at each level of B
BXC at each level of A
Is it typical for post-hoc tests on a three way interaction to perform all of the above 3 comparisons or would one typically just pick one or 2? They are all an important part of the story.
Also regarding adjustment for multiple comparisons, I have used SIDAK to adjust for for this within each of the above 3 tests. I am assuming that I do not need to adjust each p value further to account for the total number of comparisons in all 3 of the above?
Finally, most stats textbooks state that if you have an interaction term you can't reliably interpret the main effects. If I only have an interaction term for AxB, not AxC or BxC, is it still ok to interpret the main effect? Thanks for you help,