On Wed, 19 Oct 2005 10:18:02 -0700 Berton Gunter wrote: > To be pedantic (I'm feeling cranky today): > > One can never test "whether the data follow ["data" is plural] a > Poisson distribution" -- only whether there is sufficient evidence to > cast that assumption into doubt. Perhaps a better shorthand is > "whether the data are consistent with Poisonness" . This correctly > leaves open the possibility that the data are consistent with lots of > other distribution-nesses, too. I welcome alternatives, perhaps > privately to reduce the list noise level.
...now that Berton mentioned `checking distribution-nesses': the function distplot() in the package vcd implements various plots for distribution-nesses that can be used for graphical checking. Ord_plot() is made for a similar purpose. Finally, there is also a function goodfit() that computes goodness-of-fit tests for such hypotheses. All three functions are written following Chapter 2 `Fitting and Graphing Discrete Distributions' in Michael Friendly's book `Visualizing Categorical Data'. hth, Z > (And,yes, I'm sure that Thomas knows this perfectly well). > > I do think that we should be a bit less sloppy about such things even > here, lest we continue to promulgate already widespread > misunderstandings, even at the cost of slightly increased bandwidth. > After all, precision is supposed to be a major concern or ours. > > As I've been cranky, others are free to return the favor. Sauce for > the goose ... > > -- Bert Gunter > Genentech Non-Clinical Statistics > South San Francisco, CA > > "The business of the statistician is to catalyze the scientific > learning process." - George E. P. Box > > > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] On Behalf Of Thomas > > Schönhoff > > Sent: Wednesday, October 19, 2005 10:00 AM > > To: [email protected] > > Subject: Re: [R] how to test poisson distribution > > > > Hi, > > > > > > 2005/10/19, Wensui Liu <[EMAIL PROTECTED]>: > > > Dear All, > > > > > > I am wonderng how to test whether the data follows poisson > > distribution. > > > > > > Thank you so much! > > > > Did you notice the PDF on distribution tests using R by Vito Ricci, > > its found at CRAN in the docs contrib section, called "FITTING > > DISTRIBUTIONS WITH R" > > > > Maybe this could be of some help for you, especially look at page 7 > > (poisson dsitribution example). > > > > ______________________________________________ > > [email protected] mailing list > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide! > > http://www.R-project.org/posting-guide.html > > > > ______________________________________________ > [email protected] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html > ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
