I want to let the computer to calculate the estimate and standard error of β4+β5. I think I should use estimate statement but I could not understand by myself. My current code is as follows, proc mixed method=reml noclprint=10 covtest; class id; model logcd4 = week week_16 trt*week trt*week_16 / s chisq; random intercept week week_16 / subject=id type=un g gcorr; run; "week" and "week_16" are continuous variables. I don't include the effect of the "trt" at baseline because this study is supposed to be RCT. Also, I assume a different trend before and after week 16, so I include the effect of week_16. What I want to do here is to assess the effect of "trt" is different between "trt=0" and "trt=1". In my thought, The actual model statement is as follows, logCD4=β1+β2week+β3week_16+β4trt*week+β5trt*week_16 I have attached xlsx file. I appreciate any kinds of help. Thank you in advance for your help.
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