Hi,
You need a single design matrix with demeaned age as your third column.
See this example:
http://fsl.fmrib.ox.ac.uk/fsl/fslwiki/GLM#Two-Group_Difference_Adjusted_for
_Covariate
cheers,
-MH
--
Michael Harms, Ph.D.
-----------------------------------------------------------
Conte Center for the Neuroscience of Mental Disorders
Washington University School of Medicine
Department of Psychiatry, Box 8134
660 South Euclid Ave. Tel: 314-747-6173
St. Louis, MO 63110 Email: [log in to unmask]
On 9/18/14 1:36 PM, "M. alshikho" <[log in to unmask]> wrote:
>Dear FSL experts,
>I am trying to add a covariate in my TBSS analysis. I wanted to eliminate
>the confound of age covariate variable in my analysis (10 control, 10
>patients). kindly, is the following correct:
>
>CONTRAST (design.con)
>/NumWaves 2
>/NumContrasts 2
>/PPheights 1 1
>/Matrix
>1 -1
>-1 1
>
>MATRIX 1 (design.mat)
>/NumWaves 2
>/NumPoints 22
>/PPheights 1 1
>/Matrix
>1 0
>1 0
>1 0
>1 0
>1 0
>1 0
>1 0
>1 0
>1 0
>1 0
>0 1
>0 1
>0 1
>0 1
>0 1
>0 1
>0 1
>0 1
>0 1
>0 1
>
>MATRIX 2 (design2.mat)
>/NumWaves 1
>/NumPoints 22
>/PPheights 1 1
>/Matrix
>39
>48
>38
>50
>43
>27
>34
>30
>41
>41
>23
>39
>42
>44
>31
>42
>33
>31
>52
>37
>
>
>Then I used the following command line (adding the -x and the -D options)
>
>randomise -i all_FA_skeletonised -o tbss -m mean_FA_skeleton_mask -d
>design.mat -t design.con -x design2.mat -n 500 --T2 -V -D
>
>Thank you very much
>Mohamad
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