Displaying 2 results from an estimated 2 matches for "davidsonrac".
2007 Jul 20
1
cv.glm error function
I have a couple quick questions about the use of cv.glm for
cross-validation.
1. If we have a Poisson GLM with counts Y~Poisson(mu) and
ln(mu)=beta0+beta1*x1+..., is the prediction error (delta) that is output
from cv.glm provided in terms of the counts (y) or the (mu)?
2. Can cv.glm be used for negative binomial models fit using glm.nb? It
appears to work, but since NB models aren't
2007 Jul 26
1
zeroinfl() or zicounts() error
I'm trying to fit a zero-inflated poisson model using zeroinfl() from the
pscl library. It works fine for most models I try, but when I include either
of 2 covariates, I get an error.
When I include "PopulationDensity", I get this error: Error in solve.default
(as.matrix(fit$hessian)) : system is computationally singular:
reciprocal condition number = 1.91306e-34
When I