you should trun a separate fixed effects analysis on each subject and then
enter the con* images from those analyses into the two-sample model (one for
each subject).
russ
Henrik Walter wrote:
> Thanks for your answer. But what I really wanted to know is if it is better
> (more correct) to take the con*images from one Fx-Effects analysis (24
> subjects, both groups) or from two seperate Fx-Effects analysis (12 from one
> group, 12 from the other).
>
> Have you any comments?
>
> H.W.
>
> Russ Poldrack schrieb:
>
> > to do the between-groups analysis, use the two-sample t-test option under
> > basic models and then provide the subject-specific con*.img files for each
> > of your two groups. this will test for differences in that effect between
> > the groups (in either direction depending upon the contrast you specify).
> >
> > cheers
> > russ
>
> --
> Dr. Dr. Henrik Walter
> Abteilung Psychiatrie III
> Universitätsklinikum Ulm
> Leimgrubenweg 12
> 89075 Ulm
>
> fon: 0731/502 1489
> fax: 0731/502 1549
> e-mail: [log in to unmask]
--
Russell A. Poldrack, Ph. D.
Assistant Professor of Radiology, Harvard Medical School
MGH-NMR Center
Building 149, 13th St.
Charlestown, MA 02129
Phone: 617-726-4060
FAX: 617-726-7422
Email: [log in to unmask]
Web Page: http://www.nmr.mgh.harvard.edu/~poldrack
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