I would like a real-life example of a data set which one might think to
model by a binomial distribution, but which is substantially
underdispersed. I.e. a sample X = {X_1, X_2, ..., X_N} where each X_i
is an integer between 0 and n (n known a priori) such that var(X) <<
mean(X)*(1 - mean(X)/n).Does anyone know of any such examples? Do any exist? I've done a perfunctory web search, and had a look at "A Handbook of Small Data Sets" by Hand, Daly, Lunn, et al., and drawn a blank. I've seen on the web some references to underdispersed "pseudo-Poisson" data, but not to underdispersed "pseudo-binomial" data. And of course there's lots of *over* dispersed stuff. But that's not what I want. I can *simulate* data sets of the sor that I am looking for (so far the only ideas I've had for doing this are pretty simplistic and artificial) but I'd like to get my hands on a *real* example, if possible. Grateful for any pointers/suggestions. cheers, Rolf Turner -- Honorary Research Fellow Department of Statistics University of Auckland Phone: +64-9-373-7599 ext. 88276 ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
