Hi - yes, you can add new covariates for gender, which will be fine as
long as the effect is additive in the data.
Cheers.
On 21 Jul 2008, at 09:09, Longchuan Li wrote:
> Dear FSL users
>
> Right now, I have three groups data for TBSS analysis (1: control,
> 2: diseaseAlevel1, 3: diseaseAlevel2). My design matrix is like this:
>
> group subjects EV1 EV2 EV3
> 1 1 1 0 0
> 1 2 1 0 0
> 1 3 1 0 0
> 2 4 0 1 0
> 2 5 0 1 0
> 2 6 0 1 0
> 3 7 0 0 1
> 3 8 0 0 1
> 3 9 0 0 1
>
> my t-test and F-test contrasts are like this:
>
> C1 A-B 1 -1 0
> C2 A-C 1 0 -1
> C3 B-C 0 -1 1
> C4 A 1 0 0 F1
> C5 B 0 1 0 F2
> C6 C 0 0 1 F3
>
> We now suspect that gender may play a role in the FA differences
> among the three groups. So my question is:
>
> Is it possible to make gender a covariate in the design so the
> effect of gender can be controlled?
>
> Your help is greatly appreciated
>
> Longchuan
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Stephen M. Smith, Professor of Biomedical Engineering
Associate Director, Oxford University FMRIB Centre
FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK
+44 (0) 1865 222726 (fax 222717)
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