Dear all,
I have set up a flexible factorial design with age as a covariate in the second level analysis. Currently, I am defining contrasts to calculate overall F-contrast and t-tests. However, I am a bit confused with the contrast specification and have several questions:
1. Is it advisable to subtract the high level baseline from the condition I am interested in? What does this contrast actually mean at the covariate level? Is it subtracting the variance explained by the high level baseline form the variance explained by the condition?
2. How can I interpret contrasts with negative values entered in the contrast manager? Do they simply mean that the age is negatively correlated with the BOLD signal? Or does the model just estimate the shared variance regardless of positive or negative correlation?
Thank you very much in advance for your help.
Best regards,
Patrick
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