I am simulating data for a 2-groups trial with 100 subjects in each group. There are four variables: GROUP, SUBJNO, SEX, AGE. SEX and AGE are covariates for following model.
Here is my code:
%let seed=12345;
data tab1;
call streaminit(&seed.);
length subjno $4 sex $1;
do _n_=1 to 100;
group=1;
subjno='1'||put(_n_,z3.);
sex=choosec(rand('table',0.5,0.5),'M','F');
age=rand('integer',18,70);
output;
end;
do _n_=1 to 100;
group=2;
subjno='2'||put(_n_,z3.);
sex=choosec(rand('table',0.5,0.5),'M','F');
age=rand('integer',18,70);
output;
end;
run;
Unfortunately, The initial random seed, 12345, causes SEX statistical difference on different group, the p value of Chisq is 0.0477.
I have tried new seed value like 123, 1234, 123456, 1234567 and they will not cause SEX statistical difference on different group.
I know there is a possibility that statistical difference of covariates happens. Is there a way to ensure no statistical differences between groups in covariates when simulating data?
Maybe block randomization with covariates as block factor? What about continous covariate variable like AGE?
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