Sanaz,
> the term 'removed' in [covariates removed] means that the covariate is controlled for in this comparison.
You're correct that the description in the 3dttest++ help can be improved.
You seem to have a 2 x 2 data structure. If you decide to use 3dttest++ instead of 3dMVM to handle the situation, there are a couple of subtleties involved. One, it sounds like you're going to ignore the interaction effect. Two, dummy coding a categorical variable can be tricky. For example, 0/1 coding for sex could cause some unwanted side effect, If you really want to use 3dttest++,
1) make sure the assumption of no interaction is reasonable
2) code the two sexes with something -0.5 and 0.5 (or -1 and 1). See more details here: [
stats.idre.ucla.edu]
Gang
