Displaying 3 results from an estimated 3 matches for "nbii".
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nbi
2010 Jun 02
1
Problems using gamlss to model zero-inflated and overdispersed count data: "the global deviance is increasing"
...px?c=diederik.strubbe&n=23519).
First, I create a (strong) pattern in the dataset by:
data$LFAP200 <- data$LFAP200 + (data$duck*data$duck)
I try to analyze these data by fitting several possible distributions (Poisson PO, zero-inflated Poisson ZIP, negative binomial type I and type II NBI NBII and zero-inflated negative binomial ZINBI) while using cubic splines with a df=3. The best fitting model will then be choses on the basis of its AIC.
However, these models frequently fail to converge, and I am not sure why, and what to do about it. For example:
> model_Poisson <- gamlss(duc...
2014 Jul 28
0
R-devel Digest, Vol 137, Issue 25
...tween these different implementations.
In addition to MASS::glm.nb(), note msme::negbinomial(), aod::negbin() and gamlss::gamlss(). The gamlss function fits two different types of NB model, either family = NBI (quadratic; var = mu(1 + sigma * mu)) as I think for all the functions above, or family=NBII (linear; var = mu(1 + sigma)). Also note the somewhat special purpose function glmnb.fit() in the stat mod package, which requires preliminary setup steps.
John Maindonald email: john.maindonald@anu.edu.au<mailto:john.maindonald@anu.edu.au>
phone : +61 2 (6125)3473 fax :...
2007 Jan 06
2
negative binomial family glm R and STATA
Dear Lister,
I am facing a strange problem fitting a GLM of the negative binomial
family. Actually, I tried to estimate theta (the scale parameter)
through glm.nb from MASS and could get convergence only relaxing the
convergence tolerance to 1e-3. With warning messages:
glm1<-glm.nb(nbcas~.,data=zonesdb4,control=glm.control(epsilon = 1e-3))
There were 25 warnings (use warnings() to see