No problem!
Gwenaelle
PS: Next time, could you please send your email via
the FSL list? Thanks :-)!
--- Brittany Copp <[log in to unmask]> a écrit :
> That makes much more sense. Thanks!
>
> Brittany
>
> On Jan 15, 2008 6:52 PM, Gwenaëlle DOUAUD
> <[log in to unmask]> wrote:
>
> > The method you're using to correct your p-values
> for
> > multiple comparisons can give you very different
> > results so, potentially, one method could give you
> > significant results (p<0.05) while another one
> would
> > not. If, in your max images (FWE correction) or in
> > your maxc images (cluster-based corection, with
> > various thresholds such as the ones you've used)
> you
> > have *no* p-value above 0.95, then it simply means
> > that you have *no* significant result after the
> > correction for multiple comparisons offered in
> > randomise. Another option you might like to try is
> the
> > FDR correction though (fdr command line, please
> see
> > http://www.fmrib.ox.ac.uk/fsl/randomise/fdr.html).
> > If this is still not clear, you might find some
> more
> > accurate and detailed information in the FSL
> archives.
> >
> > Gwenaëlle
> >
> >
> > --- Brittany Copp <[log in to unmask]> a
> écrit :
> >
> > > I am still confused as to how this would change
> the
> > > results. I can change
> > > the -c option to 2 or even 1 and it doesn't seem
> to
> > > change anything. Is
> > > that what you meant? Thanks for all the help!
> > >
> > > Brittany
> > >
> > > On Jan 10, 2008 12:52 PM, Gwenaëlle DOUAUD
> > > <[log in to unmask]> wrote:
> > >
> > > > Yes, absolutely. It just means that your
> results
> > > do
> > > > not survive the FWE correction for multiple
> > > > comparisons (everything is lower than 0.95).
> > > Again,
> > > > FWE is a quite conservative correction so you
> may
> > > want
> > > > to play with the cluster-based correction
> > > instead...
> > > >
> > > > Gwenaelle
> > > >
> > > >
> > > > --- Brittany Copp <[log in to unmask]> a écrit :
> > > >
> > > > > For the first contrast the range is
> 0-0.2246,
> > > and
> > > > > for the second contrast
> > > > > the range is 0-0.6712 (these are both the
> > > corrected
> > > > > contrasts). The
> > > > > uncorrected are both 0-0.99. Does this make
> > > sense?
> > > > > Thanks,
> > > > >
> > > > > Brittany
> > > > >
> > > > > On Jan 10, 2008 7:55 AM, Matthew Webster
> > > > > <[log in to unmask]> wrote:
> > > > >
> > > > > >
> > > > > > Hi,
> > > > > > what is the output of
> > > > > > fslstats tbss -R
> > > > > > if it is 0 0, then it might be worth
> uploading
> > > > > your input files for us to
> > > > > > have a look at...
> > > > > >
> > > > > > Regards
> > > > > >
> > > > > > Matthew
> > > > > >
> > > > > > When I open the output files in FSLview it
> > > makes
> > > > > sense that since they are
> > > > > >
> > > > > > 1-p values that if I set the min to 0 and
> the
> > > max
> > > > > 1 that all voxels should
> > > > > >
> > > > > > light up, even in the corrected images.
> This
> > > is
> > > > > true for the uncorrected,
> > > > > >
> > > > > > but not for the FWE corrected images. Is
> this
> > > > > expected based on how the
> > > > > >
> > > > > > correction is designed?
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > >
> >
> >
>
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> >
> >
> >
> >
> >
>
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