I have a SAS related question --
I am ruing a simple linear regression, with three different groups of participants as the predictors (with group 1 as the reference), the outcome a continuous social support variable, and five covariates. Three of the covariates are dichotomized (age, sex, & education), one is a three-level nominal variable (marital status), and the last is continuous (it's a chronic disease index). My question is: do I need to specify the different types of covariates in the SAS coding somehow?
Would this coding example be correct?:
proc glm data=work.example;
class group age sex education marital education chronic_diseases;
model social_support = group age sex education marital education chronic_diseases;
estimate 'group 1 vs group 2' group -1 1 0;
estimate 'group 1 vs group 3' group -1 0 1;
run;