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Hello, I was having some trouble entering my contrasts in the analysis I am doing, so I figured I may be doing something very wrong. Here are the specifics: Single regression 44 smoothed, preprocessed PET images from different subjects (1 image per subject) Covariate = continuous variable No grand mean scaling No threshold masking With Implicit masking With mean voxel value global calculation (default) Ultimately, I want to get the equation of the line that has for the y-value voxel activation level and for the x-value the continuous variable I am interested in. When I go to enter contrasts, I am not able to enter simply a +1 and (following that) a -1 t-contrast to see how the variable goes up and down with activation. It only lets me enter an F-contrast. And it kicks back a fantastic looking fitted (adjusted) line when I enter 1 -1 for the contrast. What am I doing wrong here? Sorry for the length of the email. Just wanted to be specific about the issue. Thank you very much in advance, Aviva Olsavsky