I have similar questions too, Hanna! I tried to select a categorical variable with 3 levels in Discrete (Fixed Factors) tab, but failed.

In another analysis, I am trying to select two continuous variables in the Continuous (Covariate) tab, but qdec does not allow me to select two at one time.

Do these analyses need to be done through commands? Could anyone help me with my problems, or does anyone know an online tutorial page that I have missed?

Thank you very much in advance for your input!! Best, QJ

On Wed, Jul 2, 2014 at 10:46 AM, Isotalus, Hanna hanna.isotalus@kcl.ac.uk wrote:

Dear Freesurfer experts,

I am doing an analysis on a large data set gathered from eight different imaging centres. In my analysis I would like to covary for the imaging site but qdec only allows me to covary for categorical variables if they have two levels (and I have eight). I am also using age (continuous) and gender (categorical, two levels) as covariates.

Is there a way of using the imaging site as a covariate using qdec? Do you have any suggestions on how I should proceed? Is treating imaging site as a continuous variable acceptable?

Best wishes,

Hanna​

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