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Re: st: large numbers in comb(n,k) function: no success


From   Austin Nichols <austinnichols@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: large numbers in comb(n,k) function: no success
Date   Thu, 5 Feb 2009 12:01:01 -0500

Inna Becher <inna.becher@uni-konstanz.de>:
[comb(n-m,k)/comb(n,k)] has m terms in the numerator and denominator,
so for m=2 it may be easier to calculate by hand...

di exp((lnfactorial(180000-2)-lnfactorial(180000-2-2000)-lnfactorial(2000))-(lnfactorial(180000)-lnfactorial(180000-2000)-lnfactorial(2000)))
.97790117

di (180000-2000)*(180000-2000-1)/180000/(180000-1)
.97790117


On Thu, Feb 5, 2009 at 11:40 AM, Inna Becher
<inna.becher@uni-konstanz.de> wrote:
> Thank you, Bill. I've just spoken with a mathematician, he showed me a
> similar way you did.
> the formula I need is actually:
>
> probability=1- [comb(n-m,k)/comb(n, k)]
> so I have useful numbers after the computation. (n=180000, m=2, k=2000)
>
> Inna
>
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