The RANUNI function will generate a uniform pseudorandom variable which has values between 0 and 1. So, this is what you could do (untested);

data yourdata(drop=seed); set yourdata; retain seed 99; * using a seed bigger than zero allows you to reproduce your results!; subset = (ranuni(seed)>=0.5); * The variable SUBSET will be 0 or 1, with about a 50/50 split; run;

Then you can select your subsets using the SUBSET variable.

Bob Abelson HGSI 240 314 4400 x1374 bob_abelson@hgsi.com

Mary Beth Kaylor <witten_5@YAHOO.COM> Sent by: "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU> 10/05/2006 10:39 AM Please respond to Mary Beth Kaylor <witten_5@YAHOO.COM>

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Subject Splitting data set

Hi- I was just wondering if anyone could tell me how to split a dataset. I am working with a subset of a large survey and want to build a model with one half of the dataset and test it on the other. I want all those participants who meet the requirements to be in one of the two sets, I don't want a random sample. I was told to use the RANUNI command but am unsure how to achieve my goal. Thank you for your time and help :)