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From |
"Nick Cox" <n.j.cox@durham.ac.uk> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
RE: st: RE: Hypergeometric Distribution |

Date |
Wed, 22 Aug 2007 17:04:29 +0100 |

Apply -ln()-, -exp()- and -cond()- as needed. Nick n.j.cox@durham.ac.uk Marcello Pagano > Just concerned with the accuracy. > Nick Cox wrote: > > Roger's posting includes what I presume is an allusion to > > an -egen- function _ghyper.ado that I wrote in 1999. > > > > I withdrew this program as redundant some years ago, > > given that you can use something like > > > > comb(K, k) * comb(N - K, n - k) / comb(N, n) > > > > wherever you want. In context N, K, n, k may be > > variables, scalars or placeholders for numeric > > constants, or any mixture thereof. > > > > This might need a wrapper to yield zeros where > > appropriate, or it might need care whenever > > individual terms get very large, but otherwise > > does it raise any problems? > > > > Nick > > n.j.cox@durham.ac.uk > > > > Marcello Pagano > > > > > >> I looked at --ssizebi-- but it seems to be focused on power > >> and sample > >> sizes. > >> > > > > Newson, Roger B wrote: > > > > > >>> Thanks to Marcello for telling us all about this > recently-published > >>> algorithm, which looks very useful. A search on > >>> > >>> findit hypergeometric > >>> > >>> in Stata finds a single reference (to a SSC package), which was > >>> distributed as long ago as 1999. This suggests that the new > >>> > >> algorithm > >> > >>> might be a good candidate for implementation in Mata by > >>> > >> Marcello, or by > >> > >>> anybody else with the time and inclination to do so. > >>> > > > > Marcello Pagano > > > > > >> Does anyone have or know of Stata code to calculate the > Hypergeometric > >> Distribution accurately? > >> > >> See Journal of Discrete Algorithms , Volume 5 , Issue 2 > (June 2007) > >> Pages: 341-347 for an article by Berkopec, HyperQuick > algorithm for > >> discrete hypergeometric distribution > >> <http://portal.acm.org/citation.cfm?id=1240586&coll=GUIDE&dl=GUIDE&CFID= >> 27443384&CFTOKEN=80678482>. * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: RE: Hypergeometric Distribution***From:*Marcello Pagano <pagano@hsph.harvard.edu>

**References**:**Re: st: RE: Hypergeometric Distribution***From:*Marcello Pagano <pagano@hsph.harvard.edu>

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