Hi Olof, did mri_glmfit actually run with the FSGD file? The format is not correct. How did you convert your age variable to z? In particular, how did you demean them? Did you compute the mean on a group basis or for all subjects? What was your mri_glmfit command line?
doug




On 9/10/13 10:24 AM, olof lindberg wrote:

Dear Freesufer experts. I am trying to run attached fsgd file in qdec or in GLM-fit. I just want to do a group comparison in which I compare cortical thickness between groups controlling for age. 

when I run the analysis with age as a raw score - the results seems very strange - if i on the other hand convert age to z-scores (with a mean of 0) then results seems to be as I would expect 

As I understand it - I do not need to centre Age in order to control for it? 

So what is then going wrong when I run the analysis?

thanks

Olof


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