[R] ZINB by Newton Raphson??
Achim.Zeileis at uibk.ac.at
Mon Jun 21 07:50:57 CEST 2010
On Mon, 21 Jun 2010, cahyo kristiono wrote:
> Dear all..
> I have a respon variable y. Predictor variable are x1, x2, x3, x4, x5
> (1)?What is?the syntax to get paramater estimation of?ZINB Model by
> Newton Raphson (not BFGS)
I guess you are talking about the function zeroinfl() from the package
"pscl"? It supports all "method"s of optim() and in addition supports "EM"
estimation. Typically, all yield very similar optimized likelihood values
and associated parameters.
> (2) What syntax to plot probability of observed & predicted of ZINB
That depends on what type of predictions you want to obtain. The vignette
vignette("countreg", package = "pscl")
has some examples and further explanations.
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