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@stat.math.ethz.ch mailing list > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html