Date:         Thu, 1 Oct 1998 17:26:54 -0600
Reply-To:     Mark S Dehaan <MSD@INEL.GOV>
Sender:       "SAS(r) Discussion" <SAS-L@UGA.CC.UGA.EDU>
From:         Mark S Dehaan <MSD@INEL.GOV>
Subject:      Re: random sample selection
Comments: To: MelliJ@AOL.COM
Comments: cc: SAS-L <SAS-L@inel.gov>
Content-type: text/plain; charset=us-ascii

Melanie,
 
The basic idea is:
For every item in your population, pair it with a generated random variate
(ranuni is okay).
Then sort the data set by the random variate and use the first 20% (or
whatever) ordered
individuals.
 
psuedo code>
 
data samp; set pop;
   ranvar=ranuni(34567);
   run;
 
proc sort;
   by ranvar;
   run;
 
data mysamp; set;
   if _n_ le (36*.2);   *or whatever;
   run;
 
 
 
HTH,
Mark DeHaan
 
 
 
 
Melanie Barish <MelliJ@AOL.COM> on 10/01/98 05:06:13 PM
 
Please respond to MelliJ@AOL.COM
 
 
To:   SAS-L@UGA.CC.UGA.EDU
cc:    (bcc: Mark S Dehaan/MSD/LMITCO/INEEL/US)
Subject:  random sample selection
 
 
 
 
Hello everyone!  Can anyone give me some suggestions as to the proper code
for
a random sample selection.  Thus far, at the recommendation of a co-worker,
I
have used a ranuni command, followed by a data step with a retain
statement.
However, when attempting to select a 20% random sample, I am not getting
exactly 20%.  For instance, when I select 20% of a data set that contains
36
observations, I get 9 observations.  Thanks for the help...
 
Melanie Barish
Sr. Data Analyst
IPRO
Lake Success, NY
MelliJ@aol.com