search for: zicounts

Dear R users, I have been using the zicounts package (verson 1.1.4) in R (version 2.4.1). I have been fitting zero inflated Poisson regressions to model the number of trips made by a household. Whilst I can get the best fit parameter set from zicounts, I can't get the package to return the fitted values for the model. I have attempte...

...s fairly skewed (median = 0, mean = 1.158, 3rd qu. = 1.000). I am attempting to investigate whether plot location (four sites), species (I'm using only the four most common species), or tree dbh has a significant influence on the number of vines per tree. When I attempted to use the zicounts function, R gave me the following error message: > vines.zip<-zicounts(resp=Total.vines~.,x=~Site+Species+DBH,z=~Site +Species+DBH,distrname="ZIP",data=sycamores.1) Error in ifelse(y == 0, 1, y/mu) : dim<- : dims [product 12] do not match the length of object [549] In additi...

Dear UseRs: I have simulated data from a zero-inflated Poisson model, and would like to use a package like zicounts to test my code of fitting the model. My question is: can I use zicounts directly with the following simulated data? Create a sample of n=1000 observations from a ZIP model with no intercept and a single covariate x_{i} which is N(0,1). The logit part is logit(p_{i})=x_{i}*beta with beta=1, and...

...: system is computationally singular: reciprocal condition number = 1.91306e-34 When I include "BuildingArea", I get this error: Error in optim(fn = loglikfun, par = c(start$count, start$zero, if (dist == : non-finite finite-difference value [2] I tried fitting the models using zicounts in the zicounts library as well and had the same difficulty. When I include "PopulationDensity", it runs, but outputs only the parameter estimates, not the standard errors or p-values (those have NaN). When I include "BuildingArea", I get this error: Error in solve.default(z0...

...0 0 0 0 0 1 0 0 0 0 ... $ Scars : int 0 0 0 0 0 5 0 4 5 5 ... $ Lar : int 15 0 3 0 0 0 1 0 0 3 ... $ Mass : num 13.9 15.6 16.4 16.6 17.5 ... $ Lacfac : Factor w/ 2 levels "0","1": 1 1 1 1 1 2 1 1 1 1 ... The syntax I used to create the model is: zinb.zc <- zicounts(resp=Scars~.,x =~Location + Lar + Mass + Lar:Mass + Location:Mass,z =~Location + Lar + Mass + Lar:Mass + Location:Mass, data=alan) The error given is: Error in optim(par = parm, fn = neg.like, gr = neg.grad, hessian = TRUE, : non-finite value supplied by optim In addition: Warning messa...

Hi, I have two questions. First, I'd like to compare a ZINB model to a negativ binomial model with the Vuong test, but I can't find how to performe it from the zicount package. Does a programm exist to do it ? Second, I'd like to know in which cases we have to use a double hurdle model instead of a zero inflated model. Many thanks, St??phanie Payet REES France R??seau

Hey folks, I'm trying to do all subsets on a zero-inflated poisson regression. I'm aware of the leaps and regsubsets functions but I don't know if they work for ZIP regressions or how the syntax fits in for them. Can anyone help? The model syntax is: > zip.zc <- zicounts(resp=Scars~.,x=~Location + Lar + Mass + Lac + Lar:Mass + Location:Mass, data = alan2, distr="ZIP") Many thanks Alan Harrison Quercus Queen's University Belfast MBC, 97 Lisburn Road Belfast BT9 7BL T: 02890 972219 M: 07798615682 [[alternative HTML version deleted]]

.... ***************************************** Check out glm.nb() from package MASS fits negative binomial GLMs. ***************************************** For known theta, you can plug negative.binomial(theta) into glmmPQL() for example. (Both functions are also available in MASS.) Look at package zicounts for zero-inflated Poisson and NB models. For these models, there is also code available at http://pscl.stanford.edu/content.html which also hosts code for hurdle models. ***************************************** Consider using the function supplied in the post: https://stat.ethz.ch/pipermail/r-h...

I am interested in utilizing this so called "double hurdle" model in my study. We can write the model in the following way: if (z'a + u > 0 & x'b + e > 0) y = x'b + e, else y = 0 In the model, consumption y is the (left-) censored dependent variable. e and u are the normally distributed error terms. z'a is the participation equation and x'b is the

...on error message is An integer constant expression is required within the array subscript operator. Here is an example: double data[(*nrow)+2*env][(*ncol)+2*env]; This affects at least packages GammaTest MCMCpack MasterBayes clusterSim dprep edci epsi knnFinder pbatR rmetasim zicounts 2) Including C header files is fraught with difficulties. Unfortunately that includes the R header files, because they in turn include system C headers. The checking of which features were available was done using the C compiler with particular flags, and glibc has a habit of hiding features...

Greetings R Users! I have a data set of count responses for which I have made repeated observations on the experimental units (stream reaches) over two air photo dates, hence the mixed effect. I have been using Dr. Jim Lindsey's GLMM function found in his "repeated" measures package with the "poisson" family. My problem though is that I don't think the poisson

...29/05/2007 Tollymore 1 T11 FALSE 0 A 1 0 0 0 2 0 3 0 16.30 104 29/05/2007 Tollymore 1 T28 FALSE 0 A 0 0 0 0 0 0 0 0 14.49 And here is the syntax is used to run the ZINB with the error message, any help greatly appreciated. > zinb.zc<- zicounts(resp=Scars~.,x=~Age,z=~Age, data=alan) Error in solve.default(z0$hessian) : system is computationally singular: reciprocal condition number = 3.44599e-18 Cheers Alan Alan Harrison Quercus Queen's University Belfast MBC, 97 Lisburn Road Belfast BT9 7BL T: 02890 972219 M: 07798615682 [[a...

...;,"vegan","verification","verify","vioplot","VLMC","wavelets","wave slim","wavethresh","wccsom","WhatIf") TEMP <- c(TEMP,"wle","XML","xtable","Zelig","zicounts","zoo") #TEMP <- c(TEMP,"runfirst") #TEMP <- c(TEMP,"runfirst","base","datasets", "utils", "grDevices", "graphics","stats","methods","lmtest") print ("MODIFIED R_DEFAULT_P...