dpqr-zip function

The Zero-Inflated Poisson Distribution

Density, distribution function, quantile function and random generation for the zero-inflated Poisson (ZIP) distribution with parameters lambda and omega.

dzip(x, lambda, omega, log = FALSE)
pzip(q, lambda, omega, lower.tail = TRUE, log.p = FALSE)
qzip(p, lambda, omega, lower.tail = TRUE, log.p = FALSE)
rzip(n, lambda, omega)

Arguments

• x, q: vector of quantiles.
• p: vector of probabilities.
• n: number of random values to return.
• lambda: vector of (non-negative) means.
• omega: zero-inflation parameter.
• log, log.p: logical; if TRUE, probabilities p are given as log(p).
• lower.tail: logical; if TRUE (default), probabilities are P[X <= x], otherwise, P[X > x].

Returns

dzip gives the density, pzip gives the distribution function, qzip gives the quantile function, and rzip generates random deviates.

Examples

dzip(x = 0:10, lambda = 1, omega = 0.5)
pzip(q = c(1, 5, 9), lambda = 1, omega = 0.5)
qzip(p = c(0.25, 0.50, 0.75), lambda = 1, omega = 0.5)
set.seed(123)
rzip(n = 100, lambda = 1, omega = 0.5)

See Also

dzinb, pzinb, qzinb, and rzinb

for the zero-inflated negative binomial (ZINB) distribution.