Dear SPM expert,
I have questions about gamma value in PPM. I do the PET study use 'compared
group, 1 scan/subject' design and I try to compare the two groups diffence
in PET image. Each subject have only 1 scan.
1. From previouly mail, PPMs are based on a hierachical model for first
(voxel) and second (group) level. In my case, I only have first level
analysis. Can I use the PPM to do the statistic analysis ?
2. If this approach is sensible, which gamma value I should set (the
suggest value or zero ? if I only wish to know any significant difference
between groups). SPM give me 1SD value (for example 1.43). Does it means I
can interpretate my result as " result image shows group difference above
1.43% within 95% confidence interval ?" In this condition, should I expect
the result from PPM should be great difference from FDR result ? (actually,
I got a great difference)
thanks replay.
JLH
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