I think you misunderstand. The last question was in regard to 1 group that individual subjects were run with EV1 and EV2 paradigms. Unfortunately I ran contrasts (1,0) (0,1) (1,1). But, now I want to see activation differences between EV1 and EV2. This would have been straight forward had my contrasts been (1,-1) and (-1,1) (i believe). But, since I don't have that, may I run each subject twice and consider the EV1s and EV2s different groups so I don't have to rerun the individuals with the proper contrasts?

Thanks

On Tue, Sep 20, 2011 at 11:50 AM, Michael Harms <[log in to unmask]> wrote:
To compare groups you need to run a "Higher-level analysis" in FEAT
using the lower-level FEAT directories as inputs.  This will then create
a group contrast for each of your lower-level copes.  Assuming that you
have already created the desired lower-level copes at the individual
level, then no, you don't have to rerun individuals.

cheers,
-MH

On Tue, 2011-09-20 at 11:38 -0400, Leslie Engineering wrote:
> Or can I just treat them as two separate groups so i don't have to
> rerun individuals?
>
> On Tue, Sep 20, 2011 at 11:36 AM, Leslie Engineering
> <[log in to unmask]> wrote:
>         So I am a little confused, then. If i have individual subjects
>         that were run with two EVs contrasts (1,0) (0,1) (1,1), do I
>         have to go back and rerun each individual subject with
>         contrasts (1,-1)(-1,1) in order to get group differences or
>         can I manipulate these in some way?
>
>         On Tue, Sep 20, 2011 at 11:14 AM, Michael Harms
>         <[log in to unmask]> wrote:
>                 Group contrasts (and statistics) should be calculated
>                 from the
>                 appropriate copes, not done "post-hoc" by subtracting
>                 z-maps.
>
>                 See
>                 http://www.fmrib.ox.ac.uk/fsl/feat5/detail.html#UnpairedTwoGroupDifference
>                 which provides a clear example of how to proceed.
>
>                 cheers,
>                 -MH
>
>
>                 On Tue, 2011-09-20 at 11:07 -0400, Leslie Engineering
>                 wrote:
>                 > does it make a difference if instead I have one
>                 group that went
>                 > through a single paradigm, EV. If EV is made up of
>                 two separate
>                 > stimuli blocks and I want to separate them into  EV1
>                 and EV2, can I
>                 > run a single group average using EV1 and a single
>                 group average using
>                 > EV2 then subtract the z scores for an activation
>                 difference between
>                 > the two stimuli?
>                 >
>                 >
>                 > thanks so much
>                 >
>                 > On Tue, Sep 20, 2011 at 10:08 AM, Leslie Engineering
>                 > <[log in to unmask]> wrote:
>                 >         Hello-
>                 >
>                 >
>                 >         I ran two separate simple group average
>                 analysis. Both groups
>                 >         underwent the same fmri scan sequence.
>                 Instead of rerunning a
>                 >         group analysis and included all subjects
>                 from both groups and
>                 >         setting up contrasts for group differences
>                 (1,-1)(-1,1), is it
>                 >         statistically sound to simply subtract their
>                 zscores?
>                 >
>                 >
>                 >
>                 >
>                 >
>                 >
>
>
>
>