Rutger,
I'm assuming:
input 1 is subject1 conditionA
input 2 is subject1 conditionB
input 3 is subject2 conditionA
input 4 is subject2 conditionB etc.
Your right in that you need a group mean EV for each subject. However, you
need just one EV for the paired difference (EV1 = [1 -1 1 -1 1 -1]).
See the Paired Two-Group Difference (Two-Sample Paired T-Test) example in
the FEAT web pages for how to do this:
http://www.fmrib.ox.ac.uk/fsl/feat5/detail.html#higher
Cheers, Mark.
Mark Woolrich.
Oxford University Centre for Functional MRI of the Brain (FMRIB),
John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK.
Work: +44-(0)-1865-222782, Mobile: +44-(0)-7808-727745
On Thu, 22 Jan 2004, Goekoop, R. wrote:
> Dear FSL-users,
>
> I'd like to create a single contrast between two paired 1st level
> cope-images using a 2nd-level analysis:
>
> Input: Group: EV1 EV2 EV3
> 1 1 1 0 0
> 2 1 -1 0 0
> 3 1 0 1 0
> 4 1 0 -1 0
> 5 1 0 0 1
> 6 1 0 0 -1
> ...
>
> Since each EV only contains data from a single subject, would it still be
> necessary to include group mean EVs, indicating which inputs belong together
> (i.e. are derived from the same subject, are paired), for example:
>
> ...EV4 EV5 EV6...
> 1 0 0
> 1 0 0
> 0 1 0
> 0 1 0
> 0 0 1
> 0 0 1
> ...
>
> Or would it suffice just to specify EVs1-3 (see above),
>
> Thanks a lot,
>
> Rutger Goekoop
>
> Drs. R. Goekoop, MD.
> Department of Neurology
> Vrije Universiteit Medical Centre
> De Boelelaan 1117, P.O. Box 7057
> 1007 MB Amsterdam, the Netherlands
> Phone: 0031-20-4440316
> E-mail: <mailto:[log in to unmask]>
>
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