Beta Binomial {rmutil}R Documentation

Beta Binomial Distribution

Description

These functions provide information about the beta binomial distribution with parameters m and s: density, cumulative distribution, quantiles, and random generation.

The beta binomial distribution with total = n and prob = m has density

p(y) = B(y+s m,n-y+s (1-m)) Choose(n,y) / B(s m,s (1-m))

for y = 0, ..., n where B() is the beta function.

Usage

dbetabinom(y, size, m, s, log=FALSE)
pbetabinom(q, size, m, s)
qbetabinom(p, size, m, s)
rbetabinom(n, size, m, s)

Arguments

y vector of frequencies
q vector of quantiles
p vector of probabilities
n number of values to generate
size vector of totals
m vector of probabilities of success
s vector of overdispersion parameters
log if TRUE, log probabilities are supplied.

Author(s)

J.K. Lindsey

See Also

dbinom for the binomial, ddoublebinom for the double binomial, and dmultbinom for the multiplicative binomial distribution.

Examples

# compute P(45 < y < 55) for y beta binomial(100,0.5,1.1)
sum(dbetabinom(46:54, 100, 0.5, 1.1))
pbetabinom(54,100,0.5,1.1)-pbetabinom(45,100,0.5,1.1)
pbetabinom(2,10,0.5,1.1)
qbetabinom(0.33,10,0.5,1.1)
rbetabinom(10,10,0.5,1.1)

[Package rmutil version 1.0 Index]