Hi all,
I have been trying to use zeroinfl() with the pscl package with R version
2.1.1. and with the newest versions of the contrib packages compatible with R
2.1.1.
I have read the examples, the vignette and all the posts relating to zeroinfl()
but I am still confused as to how to structure the model.
Here is a small example; the error message is the same for big data sets
library(mvtnorm,lib.loc="C:/Documents and Settings/simonp/My Documents/R backup
library")
library(pscl,lib.loc="C:/Documents and Settings/simonp/My Documents/R backup
library")
y<-c(0,0.2,0.4,0.7,0,0,0,0.8,0,0,0,0,0)
x<-c(3,4,5,2,3,6,3,7,4,8,5,8,3)
m1<-zeroinfl(y~x|x)
Zero-Inflated Count Model
Using logit to model zero vs non-zero
Using Poisson for counts
Error in terms.formula(formula, data = data) :
argument is not a valid model
Can anyone shed any light please?
Simon.
Dr. Simon Pickett
Research Ecologist
Land Use Department
Terrestrial Unit
British Trust for Ornithology
The Nunnery
Thetford
Norfolk
IP242PU
01842750050
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