afni.nimh.nih.gov

Hello,
I'm trying to run 3dMEMA for the first time and need some clarification. I have three groups, one condition.

1. If I understand correctly, I need to use a covariate file because there are more than 3 groups, correct?

2. If so, are you coding group membership in the covariate file or contrasts?

3. If you are coding contrasts, will 3dMEMA then just run pairwise comparisons or will it also give me an omnibus effect?

Thanks!
Amanda