Re: [R] CDF of Sample Quantile

2011-03-08 Thread peter dalgaard
On Mar 7, 2011, at 19:12 , Bentley Coffey wrote: > Just to tie up this thread, I wanted to report my solution: > > When (n-1)p is an integer, there is a closed form solution: > pbinom(j-1,n,...) > > When it is not an integer, its fairly easy to approximate the solution by > interpolating betwee

[R] CDF of Sample Quantile

2011-03-07 Thread Bentley Coffey
Just to tie up this thread, I wanted to report my solution: When (n-1)p is an integer, there is a closed form solution: pbinom(j-1,n,...) When it is not an integer, its fairly easy to approximate the solution by interpolating between the closed-form solutions: fitting log(1 - probability from clo

Re: [R] CDF of Sample Quantile

2011-02-17 Thread Bentley Coffey
Duncan, I'm not sure how I missed your message. Sorry. What you describe is what I do when (n-1)p is an integer so that R computes the sample quantile using a single order statistic. My later posting has that exact binomial expression in there as a special case. When (n-1)p is not an integer then

Re: [R] CDF of Sample Quantile

2011-02-14 Thread Bentley Coffey
rneysville WV, 25430 > (304) 724-4480 > "Is the room still a room when its empty? Does the room, > the thing itself have purpose? Or do we, what's the word... imbue it." > - Jubal Early, Firefly > > r-help-boun...@r-project.org wrote on 02/14/2011 09:58:09 AM:

Re: [R] CDF of Sample Quantile

2011-02-14 Thread Duncan Murdoch
On 14/02/2011 9:58 AM, Bentley Coffey wrote: I need to calculate the probability that a sample quantile will exceed a threshold given the size of the iid sample and the parameters describing the distribution of each observation (normal, in my case). I can compute the probability with brute force

Re: [R] CDF of Sample Quantile

2011-02-14 Thread Jonathan P Daily
ly r-help-boun...@r-project.org wrote on 02/14/2011 09:58:09 AM: > [image removed] > > [R] CDF of Sample Quantile > > Bentley Coffey > > to: > > r-help > > 02/14/2011 01:58 PM > > Sent by: > > r-help-boun...@r-project.org > > I need

[R] CDF of Sample Quantile

2011-02-14 Thread Bentley Coffey
I need to calculate the probability that a sample quantile will exceed a threshold given the size of the iid sample and the parameters describing the distribution of each observation (normal, in my case). I can compute the probability with brute force simulation: simulate a size N sample, apply R's