afni.nimh.nih.gov

Amanda,

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

Yes, that's correct.

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

Through a covariate file using option -covariates.

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

Check out this web page: [afni.nimh.nih.gov]

Gang