## Randomization to 3 unequal groups

Occasional Contributor
Posts: 12

# Randomization to 3 unequal groups

I'm having a hard time understanding how to take my dataset of 6000 observations and randomize them to 3 unequal groups (1000, 1000, and 4000), and then randomize each of those into 5 equal groups (so 15 groups total). There are no strata, I only need to split the observations randomly into three unequal groups, then each of those into to five equal groups. The only variable in the dataset is ID number. I'm trying to do this with PROC SURVEYSELECT and PROC PLAN and having no luck.

Super User
Posts: 23,771

## Re: Randomization to 3 unequal groups

Can always do it the old fashion way, with creating a random number:

data want;

do ID=1 to 6000;

ran_number=rand('normal');

output;

end;

run;

proc sort data=want;

by ran_number;

run;

data want2;

set want;

if 1 <= _n_ <=1000 then group=1;

else if 1001 <= _n_ <=2000 then group=2;

else group=3;

run;

Occasional Contributor
Posts: 12

## Re: Randomization to 3 unequal groups

Okay, yes, that makes sense. Then I can take each of the 3 groups and do the same thing to randomize them to 5 equal groups. Thank you!

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