[R] Random # generator accuracy

Thomas Lumley tlumley at u.washington.edu
Fri Jul 24 00:16:39 CEST 2009


On Thu, 23 Jul 2009 Ted.Harding at 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

Thomas Lumley			Assoc. Professor, Biostatistics
tlumley at u.washington.edu	University of Washington, Seattle




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