Message-ID: <3E9A810E.1090603@pdf.com>
Date: 2003-04-14T09:36:14Z
From: Spencer Graves
Subject: Bayesian package
GAMMA-POISSON: Am I correct that the discrete marginal of a
gamma-Poisson is negative binomial? Try, "?pnbinom" for that. The
posterior is another gamma; use "?pgamma", etc., for that.
GAMMA FUNCTION WITH LARGE ARGUMENTS:
> lgamma(284)
[1] 1318.403
> gamma(284)
[1] Inf
Acceptable?
Spencer Graves
Ramon Mart?nez Coscoll? wrote:
> We are trying to obtain a predictive distribution in a Poisson model using a
> non-informative prior distribution. We have found a gamma poisson as a
> result of our analysis and we want to evaluate it in R. Is there any package
> where this distribution and anothers are defined?
>
> In any case, we have tried to programm the gammapoisson probability function
> but we have found another problem: we must evaluate a gamma function with a
> quite high value (gamma(284)). How can it be done?
>
> Thank you very much!
>
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