Dear SPM community,
We are looking for the formula to calculate the spmT from the con and ResMS
We have a simple contrast, with two 1's and all zeros
The df looking at the t-test in spm is 1760
at a certain voxel I have
spmT=0.61152
con=0.21915
ResMS=1627.34
as read-off using imagecalc.
We tried to do:
t=con/sqrt(ResMS*(1/df+1/df)), but it's off by a factor of ~2
Does any body know the formula of the top of his/her head?
We ask because we need to group the data from 4 subjects in a ffx, but
the design matrix doesn't calculate, so I was going to make a pseudo ffx
by calculating an overall f as the mean of the cons and the means of the
ResMS transformed as if they were from a single subject...
--
Christian Keysers, PhD
Assistant Professor
BCN Neuro-Imaging Center
University of Groningen
Antonius Deusinglaan 2 (room 120)
9713 AW Groningen
Phone: +31 50 3638794
Fax: +31 50 3638875
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