[R] Simulation

Barry Rowlingson b.rowlingson at lancaster.ac.uk
Wed May 13 17:45:22 CEST 2009

On Wed, May 13, 2009 at 4:26 PM, Gábor Csárdi <csardi at rmki.kfki.hu> wrote:
> On Wed, May 13, 2009 at 5:13 PM, Debbie Zhang <debbie0621 at hotmail.com> 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)
> Why not? It took 0.05 seconds on my 5 years old laptop.

 Second-guessing the user, I think she maybe doesn't want to type in
'rnorm(100,0,1)' 1000 times...

 Soln - "for" loop:

 > z=list()
 > for(i in 1:1000){z[[i]]=rnorm(100,0,1)}

now inspect the individual bits:

 > hist(z[[1]])
 > hist(z[[545]])

If that's the problem, then I suggest she reads an introduction to R...


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