Re: st: RE: Hypergeometric Distribution

[Marcello Pagano <pagano@hsph.harvard.edu>]

Why buy Stata if you are expected to do all this for yourself?

m.p.

Nick Cox wrote:
> 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>.
> > >       
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