Dear Will and SPMers,
Thank you very much for your fast and clear reply. I still have a
practical question about the correction for multiple comparisons to be
answered. In my VBM analysis comparing two groups of subjects (patients
vs. controls) I have some areas of the brain which are significant at
voxel-level FWE-corrected P-values ranging from 0.005 to 0.087 and whose
location is highly consistent with my study hypotheses. Nevertheless,
since some of them are close (0.087) but not below the FWE-corrected P-
value, I am not allowed to state in my report that I am going to discuss
only the results surviving the FWE-correction and I am forced to go for
the fall-back of FDR-correction. If I do this, I get a bunch of areas
throughout the brain, some of them having an FDR-corrected P-value less
than 0.05 but a FWE-corrected P-value of 0.998 which, I guess, are
definitely not worth being reported. But, if I decide to go for the FDR-
correction, I think I am not allowed to choose which results are really
significant and I need to report all of them even if the FWE-corrected P-
value is "unbelievably" not significant. I hope I made myself clear enough
about the problem I have been currently struggling with. Do you have any
suggestions? Thank you very much and happy holidays to you and the whole
list. Best regards,
Nico
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