VGAM (version 0.9-0)

Skellam: The Skellam Distribution

Description

Density and random generation for the Skellam distribution.

Usage

dskellam(x, mu1, mu2, log = FALSE)rskellam(n, mu1, mu2)

Arguments

x

vector of quantiles.

n

number of observations. Must be a positive integer of length 1.

mu1, mu2

See skellam

log

Logical; if TRUE, the logarithm is returned.

Value

• dskellam gives the density, and rskellam generates random deviates.

Warning

Numerical problems may occur for data if $\mu_1$ and/or $\mu_2$ are large. The normal approximation for this case has not been implemented yet.

Details

See skellam, the VGAM family function for estimating the parameters, for the formula of the probability density function and other details.

See Also

skellam, dpois.

Examples

mu1 <- 1; mu2 <- 2; x <- (-7):7
plot(x, dskellam(x, mu1, mu2), type = "h", las = 1, col = "blue",
     main = paste("Density of Skellam distribution with mu1 = ", mu1,
                " and mu2 = ", mu2, sep = ""))