VGAM (version 0.8-7)

Zageom: Zero-Altered Geometric Distribution

Description

Density, distribution function, quantile function and random generation for the zero-altered geometric distribution with parameter pobs0.

Usage

dzageom(x, prob, pobs0 = 0, log = FALSE)
pzageom(q, prob, pobs0 = 0)
qzageom(p, prob, pobs0 = 0)
rzageom(n, prob, pobs0 = 0)

Arguments

x, q

vector of quantiles.

p

vector of probabilities.

n

number of observations. If length(n) > 1 then the length is taken to be the number required.

prob, log

Parameters from the ordinary geometric distribution (see dgeom).

pobs0

Probability of (an observed) zero, called $pobs0$. The default value of pobs0 = 0 corresponds to the response having a positive geometric distribution.

Value

• dzageom gives the density and pzageom gives the distribution function, qzageom gives the quantile function, and rzageom generates random deviates.

Details

The probability function of $Y$ is 0 with probability pobs0, else a positive geometric(prob) distribution.

See Also

zageometric, zigeometric, rposgeom.

Examples

prob = 0.35; pobs0 <- 0.05; x <- (-1):7
dzageom(x, prob = prob, pobs0 = pobs0)
table(rzageom(100, prob = prob, pobs0 = pobs0))

x = 0:10
barplot(rbind(dzageom(x, prob = prob, pobs0 = pobs0),
                dgeom(x, prob = prob)),
        beside = TRUE, col = c("blue", "orange"), cex.main = 0.7, las = 1,
        ylab = "Probability", names.arg = as.character(x),
        main = paste("ZAG(prob = ", prob, ", pobs0 = ", pobs0,
                   ") [blue] vs",  " Geometric(prob = ", prob,
                   ") [orange] densities", sep = ""))