The last 2 lines of your code can be replaced with: M <- replicate(1000, sample(Y,5,replace=FALSE) )
-- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare greg.s...@imail.org 801.408.8111 > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r- > project.org] On Behalf Of Ted Harding > Sent: Tuesday, January 12, 2010 7:34 AM > To: r-help@r-project.org > Cc: ehcpieterse > Subject: Re: [R] Conditional Sampling > > On 12-Jan-10 14:00:24, ehcpieterse wrote: > > Thanks Ted, your solution does make perfect sense. > > > > The only question I still have is that I would like to sample > > the remaining 5 observations after I have randomly selected the > > first 10. Given the initial 10, I would like to sample the > > following 5 say 1,000 times to get a simulated conditional sample, > > if that makes any sense. > > > > I want to build this into an iterative process to see how the > > first sample affects the resulting samples. Even though all the > > observations have the same probabilty to get sampled, they each > > have a different expected value. > > -- > > OK, if I now understand you, you are interested in the properties > of the remaining (90) observations, given that they do not include > any of the (10) cases sampled in the first round. > > In that case, I think you should adopt the sample.int() approach > I also suggested: > > X <- (1:100) ## (or any other 100 values) > n <- sample.int(100,10,replace=FALSE) ## returns subset of (1:100) > x <- X[n] > Y <- X[-n] ## The set remaining after the first 10 were taken > ## Now you can sample repeatedly from Y until your eyes fall out. > ## So build up a matrix of (say) 1000 samples from Y: > M <- sample(Y,5,replace=FALSE) > for(i in (2:1000)){ M <- rbind(M,sample(Y,5,replace=FALSE)) } > > The repeated samples M of 5 from Y of course imply replacing each > sample of 5 back in Y, so they are available at each turn. You can > not, of course, sample 1000*5 from 100 without replacement! (Each > sample of 5 is obtained without replacement, however). > > I hope this is getting close! > Ted. > > -------------------------------------------------------------------- > E-Mail: (Ted Harding) <ted.hard...@manchester.ac.uk> > Fax-to-email: +44 (0)870 094 0861 > Date: 12-Jan-10 Time: 14:34:13 > ------------------------------ 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. ______________________________________________ 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.
