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Hello all,
I want to ask something about the deviance in a
glm(family=poisson)
As we know, when we want to compute the
Deviance, we have to compute something like that:
Dos = 2*Sum{y(i)*log(y(i)/mu(i) -
(y(i)-mu(i))}
What happens when in the response
variable (y), is there a value equal to zero y=0 ) ( this is possible as
y="counts"). log(zero)=- inf. So, what should
be done, to compute the Deviance and how S-plus computes it?
Many thanks in
advance,
Thodoris
Theodore Kypreos, Undergraduate
Student
Department of Statistics in Athens University of Economics and
Business
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