Hello! I have two doubts with the FSL:
1- I want to introduce in my matrix some categorical covariables (like gender, smoker-no_smoker..) to remove its effects from the results when comparing two groups (controls and patients), and I do not know how to do it. I put two columns for each covariable (for example: control_gender and patients_gender) In the control_gender column the patients will always hace a zero, but: What should I write for the controls? 1 for man and 2 for woman? 1 for man and -1 for woman? How can I make the software understand that these covariables are categorical and not quantitative?
2-My second question is about the demean process. I have found significative differences just when doing demean in my quantitative covariables and I don not know how right it is.. Should I do the demean even when the covariable does not have a normal distribution?
Nothing more, thank you very much.
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