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From |
Inna Becher <inna.becher@uni-konstanz.de> |

To |
statalist@hsphsun2.harvard.edu |

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

Date |
Thu, 05 Feb 2009 14:51:21 +0100 |

Thank you Maarten, I' ll try to implement it. Inna Maarten buis schrieb:

--- 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 avoidtaking 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 tothe log-likelihood function in Stata. This contains asimilar problem except that the relevant function in thebeta is the Gamma function instead of the factorial function. Stata has a -lngamma()- but no -gamma()- function, and thistext 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/

* * 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/

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

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