Dear SPM experts,
I have a question regarding the regression analysis in SPM5...
My data consists of
- 1 patient group,
- each suject underwent 2 scans (e.g. pre & post scans),
- for each of the scan and subject I have a covariate (e.g. pre & post
I first calculated the regression (scans & error rate) SEPARATELY for
each scan (pre & post), which is quite simple...
Now I want to know, if the regression for one (e.g. pre) scan is
stronger than for the other (e.g. post) scan.
Jonathan Peelle recently offered me a great explanation how to do this
if the two scans are independent using an ANOVA setting (two groups, two
covariates, contrast manager setting to 0 0 1 -1).
However, now I want to account for the dependency of the two scans (like
within a paired T-test).
I first thought simply to change the "Factors -> Independence" setting
to "No" but then the covariate within my design matrix changes and I do
not understand why!
Any suggestions would be greatly appreciated :)
Thanks a lot,