On Thu, 15 Jun 2000, Dr. Michael D. Devous, Sr. wrote:
> correlations between clusters, you might get false positives that were
> merely due to differences in uncorrected attenuation.
Instinctively I agree with the above, and have expressed a similar opinion
previously, but without any subsequent followup
(http://www.mailbase.ac.uk/lists/spm/2000-04/0013.html). There are
inevitably differing attenuation gradients within uncorrected images,
which depend upon head size. One might therefore predict false
significant M/F differences due to average head size when using
uncorrected data? I really don't have a feel for how large/significant
such effects are.
Keith.
--
Keith Goatman
Medical Physics, Southampton General Hospital, UK.
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