Also, p-values for t-tests are two-sided.
Nick Schmansky wrote:
Jeff,
sig.mgh actually stores the -log10(p), not p, so to get the true p-value of say, -2 (in the sig.mgh), take 10^-2 (giving you the true p-value of 0.01).
Nick
On Mon, 2009-06-08 at 16:48 -0600, Jeff Sadino wrote:
Hello Surfers,
I am trying to verify the p-value sig.mgh maps outputted from the mri_glmfit command as the first part of a more advanced analysis. We have been extracting the thickness data for a single vertex from each of our 58 subjects in two control groups and then running a significiance analysis is SAS. We thought that the output from SAS should match the p-value in the sig.mgh file, but the p-values do not match at all. We have tested multiple data points. Does freesurfer do some sort of a more advanced significance analysis that is not in the standard documentation?
Thank you very much, Jeff Sadino
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