Dear SPM ers:
In a large group of n=42 I have
search volume = S= 536352
fwhm 11.5, 13.2, 13.8,
205.5 resels= R
a subset of 15 subjects (of the 42)
S= 651480
fwhm 11.2, 12.3 , 13.2,
294.6 resels
1) any explanation for the large difference in S. Data are identical
and I use the same threshold for both.
2) Is there a way to constrain the search volume (since FWHM are
almost similar) to make comparison more adequate (since p value is
proportional to the number of resels (V/fwhm x y z ) or is it
unreasonable.
In other words how much a change from 200 to 300 resels will
influence p values.
Thank you for your help
Didine
--
Badreddine Bencherif, MD
Department of Radiology
Division of Nuclear Medicine
Johns Hopkins University School of Medicine
601 N. Caroline St. / JHOC 4230
Baltimore, MD 21287-0855
Phone: (410) 614-2787
Pager: (410) 283-2050
Fax: (410) 614-1977
email: [log in to unmask]
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