R: Simulate Negative Binomial Variates

rnegbin {MASS}

R Documentation

Simulate Negative Binomial Variates

Description

Function to generate random outcomes from a Negative Binomial distribution, with mean mu and variance mu + mu^2/theta.

Usage

rnegbin(n, mu = n, theta = stop("'theta' must be specified"))

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.

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
fm <- glm.nb(Days ~ ., data = quine)
dummy <- rnegbin(fitted(fm), theta = 4.5)

[Package MASS version 7.3-61 Index]