Dear SPM experts,
I have a rather basic question on SPM covariance analysis concerning PET
activation studies. When I like to perform a covariance analysis between
rCBF and a measure of motor performance during a single PET scan (lets
say mean movement time of a joystick movement during a single PET scan),
do I have to establish a normal distribution for the
covariate-of-interest? If I need to establish a normal distribution as a
prerequisite for an analysis of covariance, does this refer to the
distribution within a single scan or across scans? If the measure of
motor performance does not follow a normal distribution, is it
appropriate to transform the performance data into a normal
distribution?
Thanks
Hartwig Siebner
Dr. Hartwig R. Siebner
Department of Neurology
Motor Control Unit, Technical University
Möhlstrasse 28,D-81675 Munich,Germany
e-mail: [log in to unmask]
FAX: 0049-89-4140-4867
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