Hi all- I have been trying to determine the most appropriate way to set up an interaction contrast for glmfit. For my purposes I'm interested in looking at the interaction two performance variables while covarying demographics. I have 2 classes set to male and female and the first columns in my fsgd file are demeaned age and education.
I have found 3 ways people suggest setting up an interaction contrast: 1- Putting the contrast in one row: 0 0 0 0 -.5 -.5 .5 .5 2- Using two rows for the contrast: 0 0 0 0 .5 .5 0 0 0 0 0 0 0 0 .5 .5 3- Creating an actual interaction term where the values are multiplied together in a new column of the fsgd file 0 0 0 0 0 0 0 0 .5 .5 I would be grateful to know how people set up this contrast. Also I would like to know how you run it (positive or negative) and subsequently how you interpret the results. Thanks, Sarah Banducci
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