Hi Ben! First I thank you for your attention. Unfortunately, the ANOVA does not work with vglm. In another email, Rafael warned me that actually a lot of zeros does not necessarily imply a distribution of zeros binomail inflated. So how could I test if my variable is or not a binomial zero inflated?
Thanks. M.Sc Ivan Bezerra Allaman Zootecnista Doutorando em Produção Animal/Aquicultura - UFLA email e msn - ivanala...@yahoo.com.br Tel: (35)3826-6608/9925-6428 ________________________________ De: Ben Bolker [via R] <ml-node+2221578-2039137178-109...@n4.nabble.com> Enviadas: Terça-feira, 18 de Maio de 2010 13:34:01 Assunto: Re: Using the zero-inflated binomial in experimental designs Ivan Allaman <ivanalaman <at> yahoo.com.br> writes: > > > I'm trying to use the inflated binomial distribution of zeros (since 75% of > the values are zeros) in a randomized block experiment with four > quantitative treatments (0, 0.5, 1, 1.5), but I'm finding it difficult, > since the examples available in VGAM packages like for example, leave us > unsure of how it should be the data.frame for such analysis. Unfortunately > the function glm does not have an option to place a family of this kind I'm > about, because if I had, it would be easy, made that my goal is simple, just > wanting to compare the treatments. For that you have an idea, here is an > example of my database. > > BLOCK NIV NT MUMI > Inicial 0 18 0 [snip] > > where: NIV are the treatments; NT is the total number of piglets born; Mumi > is the number of mummified piglets NT. Mumi The variable is of interest. If > someone can tell me some stuff on how I can do these tests in R, similar to > what I would do using the function glm, I'd be grateful. > I thank everyone's attention. something like comparing the likelihoods of m1 <- vglm(cbind(MUMI,NT-MUMI)~NIV*BLOCK,zibinomial,data=mydata) m2 <- vglm(cbind(MUMI,NT-MUMI)~NIV+BLOCK,zibinomial,data=mydata) m3 <- vglm(cbind(MUMI,NT-MUMI)~BLOCK,zibinomial,data=mydata) I don't know whether the anova() method works for VGLM objects or not. By the way, 75% zeroes doesn't necessarily imply zero-inflation -- perhaps it just means a low incidence? ______________________________________________ [hidden email] 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. ________________________________ View message @ http://r.789695.n4.nabble.com/Using-the-zero-inflated-binomial-in-experimental-designs-tp2221254p2221578.html To unsubscribe from Using the zero-inflated binomial in experimental designs, click here. -- View this message in context: http://r.789695.n4.nabble.com/Using-the-zero-inflated-binomial-in-experimental-designs-tp2221254p2221635.html Sent from the R help mailing list archive at Nabble.com. [[alternative HTML version deleted]]
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