topic Simulating data per subject per visit in SAS Programming

Simulating data per subject per visit

SR79 — Fri, 03 Jun 2022 22:16:06 GMT

Hi,

I am trying to simulate a dataset for 100 subjects over the course of 10 days such that the variable y with normal distribution is repeating the same value within each subject per each day.

I have the following:

data A;

call streaminit(1);

do subject =1 to 100;

do t = 1 to 10;

y=rand('normal',1,2);

output;

label t='Day';

end;

run;

which produces:

subject day y

1 1 1.03

1 2 3.02

....

2 1 1.45

2 2 0.39

...

etc.

I want this structure:

subject day y

1 1 1.03

1 2 1.03

....

2 1 1.45

2 2 1.45

...

etc.

Any help is appreciated.

Thank you!

Re: Simulating data per subject per visit

mkeintz — Fri, 03 Jun 2022 22:28:25 GMT

So you want a normal distribution accross subjects, but no variation at all within subject, right?

If so, then modify your program by taking the RAND function outside of the inner loop, and put it in the outer loop:

data A;
  call streaminit(1);
  do subject =1 to 100;
    y=rand('normal',1,2);
    do t = 1 to 10;
      output;
    end;
  end;
  label t='Day';
run;

Re: Simulating data per subject per visit

SR79 — Sat, 04 Jun 2022 14:13:54 GMT

Perfect thanks!!