[R] Re: OC curve in "Quality Control"

[Philippe Glaziou]

WilDscOp <wildscop at yahoo.com> wrote:
> For Number 1 problem: about <http://pari.math.u-bordeaux.fr/>, sorry i 
> didnot understand what to download or what to call! From 
> <http://pari.math.u-bordeaux.fr/download.html> can you please tell me what 
> should i download and how to use(i could not find any doc)? An exact link 
> for download may be helpful:)


The download page gives links to the sources of PARI.  There is
also a self-installing MS-Windows executable there. As for the
doc, there is a menu item which reads "Documentation".  Click on
it, and there you have a user's guide, tutorial, installation
guide, ref card, manual pages. By the way, there are other
packages out there to handle large entities (on a 32-bit machine)
like 500! (Octave, Matlab, Maple, Mathematica, Yacas...). I
suggested that one because I do not know the others. 



> ----------------- ---------------------------
> For Number 3 problem: i had some problem using dhyper() because i cannot 
> match the parameters there. I used
> > N<-5000; n<-50; D<-seq(0,500,1); d<-0 # (For d = 1 i just recalculated 
> it with d<-1)
> > hypg <- (choose(D, d)* choose((N-D), (n-d)) / choose(N,n))
> instead and it surves my purpose. Anyway, is there any better procedure? I 
> could not find Hypergeometric() in the base.


You needed phyper for that specific problem, not dhyper (the help
page for dhyper explains what dhyper, phyper, qhyper and rhyper
do).

hypg <- phyper(d,D,N-D,n) 

does the job in a slightly more efficient manner. 

I would suggest that you check out the following:

help.search("hypergeometric")
?Hypergeometric 


-- 
Philippe Glaziou
Epidemiologist