Dear FreeSurfers:

I hope you can help me out with a problem in disgning my .mtx file.

I want to examine the difference among three groups (HC group, EX group and PT group). Considing gender, I have six groups as similar as the example described in http://surfer.nmr.mgh.harvard.edu/fswiki/Fsgdf6G0V. But I want to correct for age.

Then, I have 6 classes (two factors/three levels) a nd one covariate (age).

How can I compare the difference among three groups (HC group, EX group, and PT group)?

Could you please tall me how to design the contrast matrix with 12 regressors?

Thanks a zillion times!

Best wishes

shiguangli