3*2*2 Repeated Measures ANOVA - How to follow up a significant two-way interaction

Koga

New Member
#1
Hi there!

I'm currently writing my thesis on motor inhibition, using TMS. I haven't touched the stats required for a long time, and I found it difficult to find solid answers that make sense to me in the many text-books I perused.

The dependent variable of interest is MEP amplitude (continuous).
The IVs are cue condition(3 - maybe stop left, maybe stop right, no cue), hand(2 - left, right), and timepoint(go signal, shortly after go signal).

I am trying to establish whether MEP amplitude systematically varies under different cue conditions, and at different time points during the task. I expect that the cue facilitates inhibition in the cued-to-stop hand, reducing MEPS. I expect that having no cue will cause some inhibition in both hands. I expect inhibition to be lowest for the hand that is not cued to maybe stop, under cued conditions.

I ran the 3*2*2 RM ANOVA. I found a main effect of cue condition and hand, but the main effect of time point was p = .1.

There was a significant interaction between cue condition and hand.

I want advice on how I should follow up these findings, particularly the interaction.

My best guess is that I compute variable to average out the effect of timepoint, and conduct a one way anova comparing right to left at each level of the cue condition. Does that sound right?

Also, I would like to know how active this forum is, is it worth becoming a long term member? I want to exercise my statistical understanding more to avoid forgetting it again - it's horrible to feel like you're losing something you worked so hard to obtain! Thanks in advance!