Dear SPMers,
I'm trying a covariate only analysis in SPM-99 for the first time
and just want to make sure it is correct. I have 47 subjects, 1 covariate
of interest (with subject specific slope), and several nuisance variables
(global activity and scan order). When I tried to put in a contrast of 47
ones (or minus ones), it was invalid. The only contrast the program seems
to accept is a single 1 or a single -1. It then pads with zeroes,
including the columns for the covariate of interest for the other 46
subjects. Can I assume that the results are in fact the equivalent of
entering one or minus one for all 47 subjects, and not just assessing the
first subject?
Thanks, and Happy New Millenium to all!
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