Hello, I'm having an error when trying to fit the next GLM:>>model<-glm(response ~ CLONE_M + CLONE_F + HATCHING+(CLONE_M*CLONE_F) + (CLONE_M*HATCHING) + (CLONE_F*HATCHING) + (CLONE_M*CLONE_F*HATCHING), family=quasipoisson)>> anova(model, test="Chi")>Error in if (dispersion == 1) Inf else object$df.residual :missing value where TRUE/FALSE needed If I fit the same model by using the Poisson distribution, it works. I have not a clue about where the problem could be. Do you have any idea or suggestion I could try? Thank you in advance, Ana
atorso wrote:> > Hello, > > I'm having an error when trying to fit the next GLM: > >>>model<-glm(response ~ CLONE_M + CLONE_F + HATCHING > +(CLONE_M*CLONE_F) + (CLONE_M*HATCHING) + (CLONE_F*HATCHING) + > (CLONE_M*CLONE_F*HATCHING), family=quasipoisson) >>> anova(model, test="Chi") > >>Error in if (dispersion == 1) Inf else object$df.residual : > missing value where TRUE/FALSE needed > > If I fit the same model by using the Poisson distribution, it works. > > I have not a clue about where the problem could be. Do you have any > idea or suggestion I could try? > >It would help if you gave a reproducible example. The following simple example seems to work.> x = runif(100) > y = rpois(100,x) > mq = glm(y~x,family="quasipoisson") > anova(mq,test="Chi")Other points: (1) I think you're a little bit confused about R model notation. * means "main effects and all interactions", : means "interaction only". You could rewrite your model more correctly as model<-glm(response ~ CLONE_M + CLONE_F + HATCHING +(CLONE_M:CLONE_F) + (CLONE_M:HATCHING) + (CLONE_F:HATCHING) + (CLONE_M:CLONE_F:HATCHING), family=quasipoisson) or even better (compactly) as model<-glm(response ~ CLONE_M*CLONE_F*HATCHING, family=quasipoisson) although all three ways give equivalent answers since the extra main-effect terms get dropped silently. (2) you should probably use test="F" rather than test="Chisq" for a quasi- model: see Crawley 2002 and/or Venables and Ripley. -- View this message in context: http://www.nabble.com/GLM-quasipoisson-error-tp25754404p25757025.html Sent from the R help mailing list archive at Nabble.com.
atorso wrote:> > Hello, > > I'm having an error when trying to fit the next GLM: > >>>model<-glm(response ~ CLONE_M + CLONE_F + HATCHING > +(CLONE_M*CLONE_F) + (CLONE_M*HATCHING) + (CLONE_F*HATCHING) + > (CLONE_M*CLONE_F*HATCHING), family=quasipoisson) >>> anova(model, test="Chi") > > > > > > I guess that those variables are factors, and that you have empty > combinations? Make a coplot, and see whether you have data for all > combinations of the levels of your factors. Formulated differently..does > it make sense, or is it possible to fit the 3-way interaction for your > data? > > Also..you may want to use the str command to see whether "response" is > indeed coded correctly. > > Alain > >>Error in if (dispersion == 1) Inf else object$df.residual : > missing value where TRUE/FALSE needed > > If I fit the same model by using the Poisson distribution, it works. > > I have not a clue about where the problem could be. Do you have any > idea or suggestion I could try? > > Thank you in advance, > > Ana > > ______________________________________________ > R-help at 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. > >----- -------------------------------------------------------------------- Dr. Alain F. Zuur First author of: 1. Analysing Ecological Data (2007). Zuur, AF, Ieno, EN and Smith, GM. Springer. 680 p. 2. Mixed effects models and extensions in ecology with R. (2009). Zuur, AF, Ieno, EN, Walker, N, Saveliev, AA, and Smith, GM. Springer. 3. A Beginner's Guide to R (2009). Zuur, AF, Ieno, EN, Meesters, EHWG. Springer Statistical consultancy, courses, data analysis and software Highland Statistics Ltd. 6 Laverock road UK - AB41 6FN Newburgh Email: highstat at highstat.com URL: www.highstat.com -- View this message in context: http://www.nabble.com/GLM-quasipoisson-error-tp25754404p25770491.html Sent from the R help mailing list archive at Nabble.com.