3dttest++ with a covariate

Hi List experts,

I am thinking to run a 3dttest++ with a covariate. I was puzzled as I do not know how to interpret the output. I have never used a covariate for a 3dttest++. Any good pointers for me? (It seems that in the 1d (common) t test, a covariate is impossible there. Am I right? )

I only have some basic thinking on 3dANCOVA (3dMEMA?). For instance, if the interaction of “main factor x covariate” is significant, then we can report that those activation regions are covariate and that factor relevant. Am I correct?

Thanks so much in advance.
Juan

I was puzzled as I do not know how to interpret the output. I have never used a covariate for a 3dttest++.
Any good pointers for me? (It seems that in the 1d (common) t test, a covariate is impossible there. Am I right? )

Not so sure which part is puzzling in terms of the output. A covariate is just an explanatory variable in the regression model. It does not make much difference in terms of modeling as to whether the analysis is performed at the voxel or the ROI level.

I only have some basic thinking on 3dANCOVA (3dMEMA?). For instance, if the interaction of
“main factor x covariate” is significant, then we can report that those activation regions are
covariate and that factor relevant. Am I correct?

How is the interaction effect of “factor x covariate” related to the covariate analysis with 3dttest++? Do you have a factor (categorical variable) in your 3dttest++ analysis?