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Problems with randomly generating samples
3 messages · Debbie Zhang, Nordlund, Dan (DSHS/RDA), (Ted Harding)
-----Original Message----- From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of Debbie Zhang Sent: Wednesday, May 13, 2009 8:18 AM To: r-help at r-project.org Subject: [R] Problems with randomly generating samples Dear R users, Can anyone please tell me how to generate a large number of samples in R, given certain distribution and size. For example, if I want to generate 1000 samples of size n=100, with a N(0,1) distribution, how should I proceed? (Since I dont want to do "rnorm(100,0,1)" in R for 1000 times) Thanks for help Debbie
How about samples <- rnorm(1000*100,0,1) dim(samples) <- c(1000,100) Hope this is helpful, Dan Daniel J. Nordlund Washington State Department of Social and Health Services Planning, Performance, and Accountability Research and Data Analysis Division Olympia, WA 98504-5204
On 13-May-09 15:18:05, Debbie Zhang wrote:
Dear R users, Can anyone please tell me how to generate a large number of samples in R, given certain distribution and size. For example, if I want to generate 1000 samples of size n=100, with a N(0,1) distribution, how should I proceed? (Since I dont want to do "rnorm(100,0,1)" in R for 1000 times) Thanks for help Debbie
One possibility is nsamples <- 1000 sampsize <- 100 Samples <- matrix(rnorm(nsamples*sampsize,0,1),nrow=nsamples) Then each row of the matrix Samples will be a sample of size 'sampsize', the i-th can be accessed as Samples[i,], and there are 'nsamples' rows to choose from. Ted. -------------------------------------------------------------------- E-Mail: (Ted Harding) <Ted.Harding at manchester.ac.uk> Fax-to-email: +44 (0)870 094 0861 Date: 13-May-09 Time: 16:46:05 ------------------------------ XFMail ------------------------------