Simulate Negative Binomial Variates
Usage
rnegbin(n, mu=n, theta=stop("theta must be given"))
Arguments
n
|
If a scalar, the number of sample values required. If a vector,
length(n) is the number required and n is used as the mean vector if
mu is not specified.
|
mu
|
The vector of means. Short vectors are recycled.
|
theta
|
Vector of values of the theta parameter. Short vectors are recycled.
|
Description
Function to generate random outcomes from a Negative Binomial distribution,
with mean mu
and variance mu + mu^2/theta
.Details
The function uses the representation of the Negative Binomial distribution
as a continuous mixture of Poisson distributions with Gamma distributed means.
Unlike rnbinom
the index can be arbitrary.Value
Vector of random Negative Binomial variate values.Side Effects
Changes .Random.seed
in the usual way.Examples
# Negative Binomials with means fitted(fm) and theta=4.5
data(quine)
fm <- glm.nb(Days ~ ., data=quine)
dummy <- rnegbin(fitted(fm), theta=4.5)