Date:         Sat, 10 Nov 2007 08:58:01 -0500
Reply-To:     Peter Flom <peterflomconsulting@mindspring.com>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Peter Flom <peterflomconsulting@MINDSPRING.COM>
Subject:      Re: Repeated Random Sample from Data Set
Comments: To: corny1 <ptnelsonster@GMAIL.COM>
Content-Type: text/plain; charset=UTF-8

corny1 <ptnelsonster@GMAIL.COM> wrote

>I need to draw repeated random sub-samples, without replacement, from
>a dataset.  Specifically, I have data from 20 environments and 3 reps
>within each environment, n=30 individuals within each rep.  I want to
>randomly sample, say 5, environments (without replacement) and then
>randomly sample one rep from within each environment, repeated several
>thousand times (for bootstrapping).  Using the code below (simplified
>version shown) I've been able to draw samples with replacement, but I
>want without replacement.  Any ideas?

You should investigate PROC SURVEYSELECT, and look up the paper "Don't be loopy" by David Cassell

Peter