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From |
"Nick Cox" <n.j.cox@durham.ac.uk> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
RE: st: RE: Hypergeometric Distribution |

Date |
Wed, 22 Aug 2007 19:13:15 +0100 |

This is partly it. The communities are not identical, although the resemblances are greater than sometimes stated or implied, particularly by various members of the R community! The bigger explanation, in my view, for the data-handling capabilities of Stata is the existence of StataCorp. Industrial strength data management depends directly or indirectly on the kind of things more likely to be done by professional programmers. Nick n.j.cox@durham.ac.uk Newson, Roger B > Perhaps a lot of us buy Stata because, once one user has programmed a > method properly, the other users will not have to do so, because the > package can be downloaded from SSC etc. > > This is also an advantage of R (which scores on price compared to > Stata). However, most R users seem to agree that R doesn't have the > level of data-handling capabilities that we Stata users have become > accustomed to. I suspect (somebody correct me if I'm wrong) > that this is > because the R community are mostly career methodologists, who are keen > to be the first to install a new method, but are not so keen to write > data-handling software to lighten the load of people with bosses, > deadlines and other workplace afflictions. > Marcello Pagano > Why buy Stata if you are expected to do all this for yourself? 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=G UIDE&CFID= > >>> 27443384&CFTOKEN=80678482>. * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**References**:**RE: st: RE: Hypergeometric Distribution***From:*"Newson, Roger B" <r.newson@imperial.ac.uk>

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