Hi,
We are doing a group analysis using qdec with two groups, and we would like to include gender and age as covariates.
Which is the best option in order to perform a simple t-test (group1>group2 and group2>group1) and including the two covariates? (we would like them to have 'zero' weighting in the contrast matrix)
We realized that if we include 'age' as a continous factor in the dialog, qdec is performing rather an interaction analysis than a covariate.
So, would it be ok to include group and gender as fixed factors and age as nuisance, and then select the output as 'Does the average thickness accounting for gender differ between group1 and group2' (age as nuisance variable)? By checking all the possibilities this seemed the best option for us, but we would like to get a confirmation that we are doing it right.
Many thanks
Roser