Dear SPMers,
When setting up a multiple regression analysis in SPM (2nd level), do I need to centre my personality-related covariate if this is the only covariate in the model? I am running a functional connectivity analysis on resting state data (i.e. motion related covariates have already been regressed out during pre-processing) and am under the impression that centring the parametric regressor is not necessary because it is the only one in the model, hence no need for orthogonalisation?
Is this correct?
Many thanks in advance!
Cheers, Loreen
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