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From |
Maarten buis <maartenbuis@yahoo.co.uk> |

To |
statalist@hsphsun2.harvard.edu |

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

Date |
Thu, 5 Feb 2009 13:32:50 +0000 (GMT) |

--- On Thu, 5/2/09, Inna Becher wrote: > > I have to calculate probabilities for observations to > > be sampled. That's why I use exp with lnfactorial... --- On Thu, 5/2/09, Maarten buis wrote: > Looks like you want to calculate a likelihood function. Is > that right? > If so, then you can use the fact that you almost always > maximize the log likelihood, which will alow you to avoid > taking the exp of lnfactorial. Some time ago I wrote a short text on how to move from the probability density function of the beta distribution to the log-likelihood function in Stata. This contains a similar problem except that the relevant function in the beta is the Gamma function instead of the factorial function. Stata has a -lngamma()- but no -gamma()- function, and this text shows that for the computation of the likelihood a -lngamma()- function is much more convenient than a -gamma()- function. You can find this text at: http://home.fsw.vu.nl/m.buis/software/betafit.html -- Maarten ----------------------------------------- Maarten L. Buis Department of Social Research Methodology Vrije Universiteit Amsterdam Boelelaan 1081 1081 HV Amsterdam The Netherlands visiting address: Buitenveldertselaan 3 (Metropolitan), room N515 +31 20 5986715 http://home.fsw.vu.nl/m.buis/ ----------------------------------------- * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: RE: large numbers in comb(n,k) function: no success***From:*Inna Becher <inna.becher@uni-konstanz.de>

**References**:**Re: st: RE: large numbers in comb(n,k) function: no success***From:*Maarten buis <maartenbuis@yahoo.co.uk>

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