[R] Re: R 0.64.2 at CRAN

[Ben Bolker]

On 6 Jul 1999, Peter Dalgaard BSA wrote:
> 
> > 
> > Also, can someone double check the negative binomial distribution
> > documentation?  I raised the question a while ago but no one seems
> > interested.  This concerns the composite Poisson scenario: according
> > my algebra, size=(1-prob)/prob instead of its reciprocal as
> > documented.
> 
> It would seem that you're right:
> 
> > mean(rnbinom(1000,2,0.1))
> [1] 18.253
> > mean(rpois(1000,rgamma(1000,2,0.1/0.9)))
> [1] 0.224
> > mean(rpois(1000,rgamma(1000,2,0.9/0.1)))
> [1] 18.129
> 
> (and the text needs rewriting too, it's a "compound Poisson
> distribution", not "heterogeneous Poisson process", right?)
> 
> 

  Mea culpa.
  Both of these corrections are right.

  (Just out of curiousity--I know that "compound Poisson process" is
the technically correct term.  I meant "heterogeneous" in a non-technical
sense, although I can see that "compound" is better.  Does "heterogeneous"
in this context have any exact implied technical meaning?)

  Ben Bolker



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