On 23-Jul-09 22:16:39, Thomas Lumley wrote: > On Thu, 23 Jul 2009 ted.hard...@manchester.ac.uk wrote: > >> The general problem, of sampling without replacement in such a way >> that for each item the probability that it is included in the sample >> is proportional to a pre-assigned weight ("sampling with probability >> proportional to size") is quite tricky and, for certain choices >> of weights, impossible. For a glimpse of what's inside the can of >> worms, have a look at the reference manual for the 'sampfling' >> package, in particular the function samprop(): >> > > The 'sampling' package also provides a nice selection of ways to draw > PPS samples without replacement. > > -thomas
Thanks, Thomas. There is of course also the package 'pps'. Ted. -------------------------------------------------------------------- E-Mail: (Ted Harding) <ted.hard...@manchester.ac.uk> Fax-to-email: +44 (0)870 094 0861 Date: 24-Jul-09 Time: 00:00:35 ------------------------------ XFMail ------------------------------ ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.