search for: zinb2

I am running a zero inflated regression using the zeroinfl function similar to the model below: fm_zinb2 <- zeroinfl(art ~ . | ., data = bioChemists, dist = "poisson") summary(fm_zinb2) I have three questions: 1) How can I obtain a value for the parameter pie, which is the fraction of the population that is in the zero inflated model vs the fraction in the count model? 2) For any part...

Are you referring to the zeroinfl() function in the countreg package? If so, I think predict(fm_zinb2, type = "zero", newdata = some.new.data) will give you pi for each combination of covariate values that you provide in some.new.data where pi is the probability to observe a zero from the point mass component. As to your second question, I'm not sure that's possible, for any *p...

Hello, I have a data frame with 1425 observations, 539 of which are zeros. I am trying to fit the following ZINB: f3<-formula(Nbr_Abs~ Zone * Year + Source) ZINB2<-zeroinfl(f3, dist="negbin", link= "logit", data=TheData, offset=log(trans.area), trace=TRUE) Zone is a factor with 4 levels, Year a factor with 27 levels, and Source a factor with 3 levels. Nbr_Abs is counts of a species that shows a high level of aggregation. These counts...

...mton.edu> >> To: "Sorkin, John" <jsorkin at som.umaryland.edu>, "r-help at r-project.org >> (r-help at r-project.org)" <r-help at r-project.org> >> Subject: Re: [R] Obtaining a value of pie in a zero inflated model >> (fm-zinb2) >> Message-ID: <02c6fe89-ccae-6c7c-c61e-f79cffad4358 at binghamton.edu> >> Content-Type: text/plain; charset="utf-8" >> >> Are you referring to the zeroinfl() function in the countreg package? If so, I >> think >> >> predict(fm_zinb2, type...