Great! Thanks so much!

-- 
Yung-Jui "Daniel" Yang, PhD
Postdoctoral Researcher
Yale Child Study Center
New Haven, CT
(203) 737-5454

On 9/5/13 5:10 PM, "Douglas N Greve" <greve@nmr.mgh.harvard.edu> wrote:


This is treating Dx and Sex as a continuous variable. I've never seen it
done before and don't recommend it, but if you want to do it, set up a
FSGD file with one group (eg, Main) and two variables. See the FSGD page
on the wiki

doug




On 09/05/2013 03:04 PM, Yang, Daniel wrote:
Sex is a nominal variable but can be coded as 0,1.

If it's coded as 0 (male), 1 (female); then the slope means,
independent of Diagnosis, how much thicker the brain the female (vs.
male) is.

But if I model Sex as a nominal variable, there is always an
interaction term between Diagnosis and Sex in qdec, whether DODS or DOSS.

I would prefer not modeling the interaction term, but I don't know how
to do so in qdec or mri_glmfit.

Daniel


--
Yung-Jui "Daniel" Yang, PhD
Postdoctoral Researcher
Yale Child Study Center
New Haven, CT
(203) 737-5454

On 9/5/13 11:27 AM, "Douglas N Greve" <greve@nmr.mgh.harvard.edu


     what does a slope of Sex mean? Is Sex a continuous variable?


     On 09/05/2013 11:03 AM, Yang, Daniel wrote:

         Hi Doug,

         So I have two variables: Diagnosis (patient vs. control) and Sex
         (female vs. male).

         My model would be:

         cortical thickness = intercept + (slope1 * Diagnosis) +
         (slope2 * Sex).

         Thanks!
         Daniel


         --
         Yung-Jui "Daniel" Yang, PhD
         Postdoctoral Researcher
         Yale Child Study Center
         New Haven, CT
         (203) 737-5454

         On 9/4/13 10:10 PM, "Douglas Greve" <greve@nmr.mgh.harvard.edu
         <mailto:greve@nmr.mgh.harvard.edu%3E>> wrote:


              I'm not sure you can do that with a linear model. What
         would your
              model look like?
              doug



              On 9/4/13 9:18 PM, Yang, Daniel wrote:

                  Hi Freesurfer,

                  Is it possible to specify only two main effects but no
                  interaction effect by using mri_glmfit?

                  If yes, could you provide an example?

                  Details are much appreciated!

                  Thanks!
                  Daniel

                  --
                  Yung-Jui "Daniel" Yang, PhD
                  Postdoctoral Researcher
                  Yale Child Study Center
                  New Haven, CT
                  (203) 737-5454

                  On 9/3/13 8:45 PM, "Yang, Daniel"
                  <mailto:yung-jui.yang@yale.edu>
             <mailto:yung-jui.yang@yale.edu%3E>> wrote:

                      Dear FS Experts,

                      My model has two categorical variable: Diagnosis
             and Sex. I
                      am interested in the effect of Diagnosis but I
             want to
                      control the Sex effect. Toward this goal, I want
             to model two
                      main effects and want to avoid modeling their
             interaction
                      term. Is this something feasible in FreeSurfer group
                      analysis? Would using DOSS help with the solution?

                      Thanks!
                      Daniel
             _______________________________________________
                      Freesurfer mailing list
             Freesurfer@nmr.mgh.harvard.edu
             <mailto:Freesurfer@nmr.mgh.harvard.edu>
                      <mailto:Freesurfer@nmr.mgh.harvard.edu>


                      The information in this e-mail is intended only
             for the
                      person to whom it is
                      addressed. If you believe this e-mail was sent to
             you in
                      error and the e-mail
                      contains patient information, please contact the
             Partners
                      Compliance HelpLine at
             http://www.partners.org/complianceline . If the e-mail was
                      sent to you in error
                      but does not contain patient information, please
             contact the
                      sender and properly
                      dispose of the e-mail.




             _______________________________________________
                  Freesurfer mailing list
             Freesurfer@nmr.mgh.harvard.eduhttps



     --
     Douglas N. Greve, Ph.D.
     MGH-NMR Center
     Phone Number: 617-724-2358
     Fax: 617-726-7422

     Bugs: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting
     www.nmr.mgh.harvard.edu/facility/filedrop/index.html
     Outgoing:



--
Douglas N. Greve, Ph.D.
MGH-NMR Center
greve@nmr.mgh.harvard.edu
Phone Number: 617-724-2358
Fax: 617-726-7422

Bugs: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting
FileDrop: https://gate.nmr.mgh.harvard.edu/filedrop2
www.nmr.mgh.harvard.edu/facility/filedrop/index.html
Outgoing: ftp://surfer.nmr.mgh.harvard.edu/transfer/outgoing/flat/greve/