I would like your help just to clarify that I'm doing the right thing,
I have at the 2nd level ran multiple regression with 1st covariate as 1st group and 2nd cov as 2nd group
then I subtract one form the other for my contrast
but now I want to check that questionnaire results for e.g. when added as a covariate of no interest
doesn't acc for too much of the data and the results are still signif
to do this should I just then add the quest data in as a third covariate and continue as norm ?
and if so, the design matrix ends up with the 1st group as 1st column then the questionnaire data as second column then the second group as the third column does this matter?
then I do 1 0 -1 for eg.
Is this right?
Thanks in advance for help
Dr Ciara McCabe
University of Oxford
Dept of Psychiatry
[log in to unmask]