Re: [Freesurfer] How can I include 3 covariates in my GLM model

you can select age, IQ and mean thickness as 'nuisance' variables, and then your group can be the main discrete variable.

as for mean thickness causing a failure, it it probably the case that the values are too close to each other. treating mean thickness as a covariate is probably not necessary anyway.

n.

On Tue, 2011-09-20 at 16:23 -0600, Dalwani, Manish wrote:

Hello Freesurfer’s,

I am using QDEC and I have created and FSGD descriptor file with 2 groups (pts and ctrls) and three continuous variables: age, IQ and mean thickness. I have 2 questions:

 1. I can only choose 2 covariates at one time? How can I choose
    all three covariates in one model in my design?
 2. I tried group and 2 covariates combinations to check if it
    runs ok and found that when I select age and IQ, it
    runs...when I select IQ and mean thickness it runs but it
    fails when I try running with age and mean thickness in the
    model? The error in the terminal says matrix not correct,
    check duplicates..., etc..

What I am doing wrong?

Thanks, Manish Dalwani _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer