I'm struggling to conceptualize the appropriate contrasts for my cortical thickness analysis. I have four classes [two groups; two levels (patients,controls; male,female) and two behavioral variables. I want to see if together the two variables account significant proportion of the variance in y (thickness) and if this differs by group whilst regressing out gender. - i.e. if I enter both behavioral variables into the model does it account for more variance than either variable on their own (after controlling for gender)? What I have is this: 

.5 .5 -.5 -.5 0 0 0 0

0 0 0 0 .5 .5 -.5 -.5

Does this look right? 

Thanks! 

Laura. 

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Laura M. Tully, MA
Social Neuroscience & Psychopathology, Harvard University
Center for the Assessment and Prevention of Prodromal States, UCLA Semel Institute of Neuroscience
ltully@mednet.ucla.edu 
ltully@fas.harvard.edu
310-267-0170
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