[R] How to do multi-factor stratified sampling in R

[Robert A LaBudde]

At 03:54 PM 3/8/2008, David Winsemius wrote:
>"Robert A. LaBudde" <ral at lcfltd.com> wrote in
>news:0JXF00LSO864ATE0 at vms040.mailsrvcs.net:
>
> > Given a set of data with a number of variables plus a response, I'd
> > like to obtain a randomized subset of the rows such that the
> > marginal proportions of each variable are maintained closely in the
> > subset to that of the dataset, and possibly maintaining as well the
> > two-factor interaction marginal proportions as well for some pairs.
> >
> > This must be a common problem in data mining, but I don't seem to be
> > able to locate the proper library or function for doing this in R.
> >
> > Thanks for any help.
>
>Have you looked at the "sampling" package? I have never used it, but the
>strata() function appears to be capable.

Thank you for pointing out this package and function. It is going to 
be very useful. I'll have to look into how I'm searching R, as 
'sampling' and 'stratified' should have turned this up.

I will spend some time looking at how strata() works to see how well 
it handles the problems I'm looking at.

Thanks again.

================================================================
Robert A. LaBudde, PhD, PAS, Dpl. ACAFS  e-mail: ral at lcfltd.com
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