Message-ID: <CANW7wbdigTVrs+Y211KHx=vLcrR=Gz6knYs0zbi4B2YO9th_6Q@mail.gmail.com>
Date: 2016-11-18T04:29:10Z
From: Pin chanratana
Subject: Mixed effect model, Hurdle function
Hi everyone here,
My name's Ratana, and I'm a Msc. student studying conservation ecology.
I'm new to the using of mixed effects model. I try to fit the mixed effect
models include an offset term (which is trapnight) of my camera-trap data
by using hurdle function. The following are the model that I fit.
m1 <- hurdle(GI ~
depth+Ele+dRoad+offset(log(TN))|depth+Ele+offset(log(TN)), data=ndata2,
dist="poisson", zero.dist="poisson")
m2 <- hurdle(GI ~ depth+Ele+dRoad+offset(TN2)|depth+Ele+offset(TN2),
data=ndata2, dist="poisson", zero.dist="poisson")
GI: Giant ibis
depth: depth of waterholes
Ele: Elevation
dRoad: distance to Road
TN: Trap-night
TN2: standardize or scale of Trap-night
But, I could not fit model m1 and there are error message: Error in
glm.fit(X, Y, family = poisson(), weights = weights, offset = offsetx) :
NA/NaN/Inf in 'y'
Model m2 is work fine and the result look reasonable.
I would like to ask if anyone know, is the way I do with model 2 is correct
by standardize the Trap-night that's use for offset in the fitting model?
If it's ok to do so, is there any reference (that I can cite) regarding to
this kind of process ?
Regards,
Ratana
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