Hi Thierry, You're very right and I was very wrong. It's a warning indeed, and the outcome is close to what I become if I calculate the logit transformation myself (although not exactly the same, but I guess that has to do with the correction the logit function does when p=0 or p=1).
I should have paid more attention to the course of categorical ;-) Kind regards Joris On Wed, Mar 25, 2009 at 10:32 AM, ONKELINX, Thierry < thierry.onkel...@inbo.be> wrote: > Hi Joris, > > glm() handles proportions but will give you a warning (and not an error) > about non-integer values. So if you get an error then there should be > something wrong with the syntax, model or data. Can you provide us with > a reproducible example? > > Cheers, > > Thierry > > > ------------------------------------------------------------------------ > ---- > ir. Thierry Onkelinx > Instituut voor natuur- en bosonderzoek / Research Institute for Nature > and Forest > Cel biometrie, methodologie en kwaliteitszorg / Section biometrics, > methodology and quality assurance > Gaverstraat 4 > 9500 Geraardsbergen > Belgium > tel. + 32 54/436 185 > thierry.onkel...@inbo.be > www.inbo.be > > To call in the statistician after the experiment is done may be no more > than asking him to perform a post-mortem examination: he may be able to > say what the experiment died of. > ~ Sir Ronald Aylmer Fisher > > The plural of anecdote is not data. > ~ Roger Brinner > > The combination of some data and an aching desire for an answer does not > ensure that a reasonable answer can be extracted from a given body of > data. > ~ John Tukey > > -----Oorspronkelijk bericht----- > Van: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] > Namens joris meys > Verzonden: dinsdag 24 maart 2009 20:30 > Aan: R-help Mailing List > Onderwerp: [R] modelling probabilities instead of binary data with > logisticregression > > Dear all, > > I have a dataset where I reduced the dimensionality, and now I have a > response variable with probabilities/proportions between 0 and 1. I > wanted > to do a logistic regression on those, but the function glm refuses to do > that with non-integer values in the response. I also tried lrm, but that > one > interpretes the probabilities as different levels and gives for every > level > a different intercept. Not exactly what I want... > > Is there a way to specify that the response variable should be > interpreted > as a probability? > > Kind regards > Joris > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list > 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. > > Dit bericht en eventuele bijlagen geven enkel de visie van de schrijver > weer > en binden het INBO onder geen enkel beding, zolang dit bericht niet > bevestigd is > door een geldig ondertekend document. The views expressed in this message > and any annex are purely those of the writer and may not be regarded as > stating > an official position of INBO, as long as the message is not confirmed by a > duly > signed document. > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list 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.
