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classification using zero-inflated negative binomial mixture model
2 messages · Kai Ying, Ben Bolker
Kai Ying <yingk <at> iastate.edu> writes:
Hi,
I want using zero-inflated negative binomial regression model to
classify data(a vector of data), that is I want know each observed value is
more likely belong to the "zero" or "count" distribution(better with
relative probability). My data is some like:
count site samp
12909 1 1
602 1 2
50 1 3
1218 1 4
91291 1 5
while "count" is the data with a mixture of "zero" and "non-zero"
distribution I want know, and "site", "samp" are two prediction valuables
with additive effect(but I am not interested in it).
I have tried the zeroinfl function of pscl package to fit zero-inflated
negative binomial regression. But it can not give you the classification
result of "count". Can anyone help with some indication of how to do it or
other tools that can do this job ??
Not sure, but you may be able to do this by hand. For a predicted mean value mu, overdispersion parameter k, and zero-inflation probability p, the probability p_z of a structural zero is p, while the probability of a sampling zero p_s is (k/(mu+k))^k ; therefore the probability that an observed zero is a structural zero is p_z/(p_s+p_z) ...