[R] Question about biasing in sd()???

2005-03-09 Thread Roy Werkman
Hi, Can anyone help me with the following. I have been using R for Monte Carlo simulations and got some results I couldn't explain. Therefor I performed following short test: -- mean.sds - NULL sample.sizes - 3:30 for(N in sample.sizes){ dum - NULL for(I in 1:5000){ x -

RE: [R] Question about biasing in sd()???

2005-03-09 Thread Liaw, Andy
Where in the help file of sd() do you see the claim that it produces unbiased estimate? Try the following: sample.sizes - 3:30 reps - 5000 set.seed(1) mean.vars - sapply(sample.sizes, function(n) mean(sd(matrix(rnorm(n*reps), nc=reps))^2)) plot(sample.sizes,mean.vars) I.e.,

Re: [R] Question about biasing in sd()???

2005-03-09 Thread Peter Dalgaard
Roy Werkman [EMAIL PROTECTED] writes: Hi, Can anyone help me with the following. I have been using R for Monte Carlo simulations and got some results I couldn't explain. Therefor I performed following short test: -- mean.sds - NULL sample.sizes - 3:30 for(N in