RTMBdist (version 0.1.0)

ztbinom: Zero-truncated Binomial distribution

Description

Probability mass function, distribution function, and random generation for the zero-truncated Binomial distribution.

Usage

dztbinom(x, size, prob, log = FALSE)
pztbinom(q, size, prob, lower.tail = TRUE, log.p = FALSE)
rztbinom(n, size, prob)

Value

dztbinom gives the probability mass function, pztbinom gives the distribution function, and rztbinom generates random deviates.

Arguments

x, q

integer vector of counts

size

number of trials

prob

success probability in each trial

log, log.p

logical; return log-density if TRUE

lower.tail

logical; if TRUE, probabilities are \(P[X \le x]\), otherwise, \(P[X > x]\).

n

number of random values to return.

Details

This implementation allows for automatic differentiation with RTMB.

By definition, this distribution only has support on the positive integers (1, ..., size). Any zero-truncated distribution is defined as $$P(X=x | X>0) = P(X=x) / (1 - P(X=0)),$$ where \(P(X=x)\) is the probability mass function of the corresponding untruncated distribution.

Examples

set.seed(123)
x <- rztbinom(1, size = 10, prob = 0.3)
d <- dztbinom(x, size = 10, prob = 0.3)
p <- pztbinom(x, size = 10, prob = 0.3)