[R] Sampling in R

[Thomas Petzoldt]

Does the following what you want:

x <- 1:100
s <- matrix(0, nrow=200, ncol=9)
for (i in 1:200) {
  s[i, ] <- sample(x, 9)
}
m <- rowMeans(s)
hist(m)


The default behavior of sample is without replacement.


Thomas


Noam Friedman wrote:
> > Hi all!
> >
> >
> > I was wondering if you can help me with a little sampling issue I'm
> > having in R.
> >
> > I have a database with 100 observations.
> > I need to sample n=9 sample size, 200 times (i.e. get 200 samples of
> > size 9).
> > N (pop. size) =100
> >
> > Each sample can't contain the same observation more than one time
> > (i.e. the program needs to check if the obs. has already been sampled
> > into the sample - it it has, it should put it back and sample again
> > another obs.)
> >
> > obviously  I need to do this with replacement.
> >
> > Then, I need to draw (I think the best is with a histogram) the
> > distribution of the mean of each os the 200 samples.
> >
> > I guess I need to do a loop for the 'sample' function in R.
> >
> > I could really use your help.
> >
> >
> > Regards,
> >
> >
> > Noam Friedman.
> >
> > ______________________________________________
> > R-help at stat.math.ethz.ch mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
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