hello everyone! I want to see whether the ComCat variable changes with sddsrvyr in the three category variable agegroup, that is, whether there is interaction between ComCat and sddsrvyr in different agegroups.
here is my code :
proc genmod data=diffcomcat;
class agegroup; weight wtmec12yr;
model comcat=agegroup sddsrvyr sddsrvyr*agegroup/ dist=p link =log type3 wald;
run;
But the line in agegroup=3 is 0 and there is no p-value, I don't understand it.
I want to ask whether the code is correct, and then how to understand the result.