Hi Dennis, Thanks - these were the first things I tried, but the problem is that they refuse to work with non-count data... Mikhail
On Wed, Mar 30, 2011 at 12:56 PM, Dennis Murphy <djmu...@gmail.com> wrote: > Hi: > > You might want to consider hurdle models in the pscl package. > > HTH, > Dennis > > On Wed, Mar 30, 2011 at 2:41 AM, a11msp <absorbt...@gmail.com> wrote: >> >> Hello, >> >> I'd like to implement a regression model for extremely zero-inflated >> continuous data using a conditional approach, whereby zeroes are >> modelled as coming from a binary distribution, while non-zero values >> are modelled as log-normal. >> >> So far, I've come across two solutions for this: one, in R, is >> described in the book by Gelman & Hill >> (http://www.amazon.com/dp/052168689X), where they just model zeros and >> non-zeros separately and then bring them together by simulation. I can >> do this, but it makes it difficult to assess the significance of >> regression coefficients wrt to zero and each other. >> >> Another solution I have been pointed at is in SAS: >> http://listserv.uga.edu/cgi-bin/wa?A2=ind0805A&L=sas-l&P=R20779, >> where they use NLMIXED (with only fixed effects) to specify their own >> log-likelihood function. >> I'm wondering if there's any way to do the same in R (lme can't deal >> with this, as far as I'm aware). >> >> Finally, I'm wondering whether anyone has experience with the COZIGAM >> package - does it do something like this? >> >> Many thanks, >> Mikhail >> >> ______________________________________________ >> R-help@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide >> http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. > > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
