Hi Naama,
That model should give you the correct result.
If you decide you want to additionally adjust for a group/site
interaction, you could follow this 2 way ANOVA model
http://www.fmrib.ox.ac.uk/fsl/feat5/detail.html#ANOVA2factors2levels
Actually t tests from that model (without the interaction term) should
be equivalent to the t test in your model.
Cheers,
Jeanette
On 9/20/07, Naama Barnea-Goraly <[log in to unmask]> wrote:
>
>
>
> Dear FSL experts,
>
> My apologies for the basic question.
>
> I would like to add a confound covariate in randomise using FSL4, I have two
> groups, in each group some subjects were scanned at site A and some at site
> B and I would like to test for between group differences while removing
> between-site differences (I know this is problematic but I want to test it
> out). I added a third EV for the different sites (see below) is that right?
> and would my contrast would be:
>
> 1 -1 0
> -1 1 0
>
> Thanks,
>
> Naama
>
>
> /NumWaves 3
> /NumPoints 46
> /PPheights 1.000000e+00 1.000000e+00 2.000000e+00
>
> /Matrix
> 1.000000e+00 0.000000e+00 1.000000e+00
> 1.000000e+00 0.000000e+00 1.000000e+00
> 1.000000e+00 0.000000e+00 1.000000e+00
> 1.000000e+00 0.000000e+00 1.000000e+00
> 1.000000e+00 0.000000e+00 1.000000e+00
> 1.000000e+00 0.000000e+00 1.000000e+00
> 1.000000e+00 0.000000e+00 1.000000e+00
> 1.000000e+00 0.000000e+00 1.000000e+00
> 1.000000e+00 0.000000e+00 2.000000e+00
> 1.000000e+00 0.000000e+00 2.000000e+00
> 1.000000e+00 0.000000e+00 2.000000e+00
> 1.000000e+00 0.000000e+00 2.000000e+00
> 1.000000e+00 0.000000e+00 2.000000e+00
> 1.000000e+00 0.000000e+00 2.000000e+00
> 1.000000e+00 0.000000e+00 2.000000e+00
> 1.000000e+00 0.000000e+00 2.000000e+00
> 1.000000e+00 0.000000e+00 2.000000e+00
> 1.000000e+00 0.000000e+00 2.000000e+00
> 1.000000e+00 0.000000e+00 2.000000e+00
> 1.000000e+00 0.000000e+00 2.000000e+00
> 1.000000e+00 0.000000e+00 2.000000e+00
> 1.000000e+00 0.000000e+00 2.000000e+00
> 1.000000e+00 0.000000e+00 1.000000e+00
> 1.000000e+00 0.000000e+00 1.000000e+00
> 1.000000e+00 0.000000e+00 1.000000e+00
> 1.000000e+00 0.000000e+00 1.000000e+00
> 1.000000e+00 0.000000e+00 1.000000e+00
> 0.000000e+00 1.000000e+00 1.000000e+00
> 0.000000e+00 1.000000e+00 1.000000e+00
> 0.000000e+00 1.000000e+00 1.000000e+00
> 0.000000e+00 1.000000e+00 1.000000e+00
> 0.000000e+00 1.000000e+00 1.000000e+00
> 0.000000e+00 1.000000e+00 1.000000e+00
> 0.000000e+00 1.000000e+00 1.000000e+00
> 0.000000e+00 1.000000e+00 1.000000e+00
> 0.000000e+00 1.000000e+00 1.000000e+00
> 0.000000e+00 1.000000e+00 2.000000e+00
> 0.000000e+00 1.000000e+00 2.000000e+00
> 0.000000e+00 1.000000e+00 1.000000e+00
> 0.000000e+00 1.000000e+00 2.000000e+00
> 0.000000e+00 1.000000e+00 2.000000e+00
> 0.000000e+00 1.000000e+00 2.000000e+00
> 0.000000e+00 1.000000e+00 2.000000e+00
> 0.000000e+00 1.000000e+00 2.000000e+00
> 0.000000e+00 1.000000e+00 1.000000e+00
> 0.000000e+00 1.000000e+00 1.000000e+00
>
>
>
> Naama Barnea-Goraly M.D.
> Research Associate
> Center for Interdisciplinary Brain Sciences Research
> Stanford University Division of Child and Adolescent Psychiatry
> 401 Quarry Rd. MC 5795
> Stanford University School of Medicine
> Stanford, CA 94305-5795
> fax: (650) 724-4794
> Phone: (650) 724-3779
>
>
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>
>
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