> Date: Thu, 17 Nov 2011 17:50:46 +0100
> From: [hidden email] > To: [hidden email] > Subject: [R] How to Fit Inflated Negative Binomial
> Dear All,
> I am trying to fit some data both as a negative binomial and a zero
> inflated binomial.
> For the first case, I have no particular problems, see the small snippet
> library(MASS) #a basic R library
> set.seed(123) #to have reproducible results
> x4 <- rnegbin(500, mu = 5, theta = 4)
> #Now fit and check that we get the right parameters
> fd <- fitdistr(x4, "Negative Binomial")
> #and mu and theta are as expected
> #now I add artificially some zeros
> x5 <- sample(c(x4,rep(0,100)))
> However, when I artificially add some zeros (case of x5) I am unsure
> about how to proceed.
> I found some material online
> http://bit.ly/uPVzOT > http://bit.ly/rXnzKi >
> but I wonder if they are an overkill of what I am really after (a
> fitting a negative binomial with too many zeros).
> Any suggestion is really appreciated.
> Many thanks
> [hidden email] 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.
> try: library(pscl)
> There's a zeroinfl for zero inflated neg. binom.
> > Dear All,
> > I am trying to fit some data both as a negative binomial and a zero
> > inflated binomial.
> > For the first case, I have no particular problems, see the small snippet
> > below
set.seed(123) #to have reproducible results
## You don't actually need MASS::rnegbin, rnbinom in base
## R works fine (different parameter names)
x6 <- c(rep(0,100),rnbinom(500,mu=5,size=4))
## sample() is irrelevant, it just permutes the results