Hi - in "normal" GLM yes, in permutation testing no - the single
group mean in a two-group model doesn't work because you need the
special case of a one-group model to do a one-group test (it flips
the sign of the data instead of the labelling of the subject (etc) ID).
Cheers.
On 17 Jul 2007, at 15:03, Peter Fried wrote:
> Hi All,
>
> Should the <output>_max_tstat from a one-sample T-test (run on a
> single
> group) be roughly equivalent to the group mean contrast (for that same
> group) from a two-sample T-test?
>
> Thanks,
> Pete Fried
> Center for Magnetic Resonance Research
> University of Minnesota
------------------------------------------------------------------------
---
Stephen M. Smith, Professor of Biomedical Engineering
Associate Director, Oxford University FMRIB Centre
FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK
+44 (0) 1865 222726 (fax 222717)
[log in to unmask] http://www.fmrib.ox.ac.uk/~steve
------------------------------------------------------------------------
---
|