Hello all,

I am using mri_glmfit (DODS method) to run a CT analysis with 2 groups and 4 covariates and have a couple of questions regarding the statistical tests performed within the group analyses:

 

1. Can Freesurfer test the change in model fit or delta R-squared in a hierarchical regression?  As far as I can tell, there is only simultaneous regression.  Alternatively, can I change the Sum of Squares Type to Type 1 (I think default is Type 3) to simulate a hierarchical regression?

2. I think the default model in FreeSurfer accounts for all other main effects.  But, does it also account for all 2 and 3 way interactions, whether or not I specify any?  In other words, is the default a fully factorial model?

 

Thank you very much for your time!

-Elizabeth