Hi everyone,
I have a question with respect to handling co-variates in a one way ANOVA in order to evaluate group differences and controlling for a covariate such as age (is an effect still there when entering age as covariate). However, from the SPM manual it is not quite clear to me how SPM12 is handling this now. The manual says:
"This option allows for the specification of covariates and nuisance variables. Unlike SPM94/5/6,
where the design was partitioned into effects of interest and nuisance effects for the computation
of adjusted data and the F-statistic (which was used to thresh out voxels where there appeared
to be no effects of interest), SPM does not partition the design in this way anymore. The only
remaining distinction between effects of interest (including covariates) and nuisance effects is their
location in the design matrix, which we have retained for continuity. Pre-specified design matrix
partitions can be entered."
Can anyone help me to clarify this issue? Thanks a lot in advance!
Best,
Stephan
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