invgamma {Boom}

Inverse Gamma Distribution

Description

Density, distribution function, quantile function, and random draws from the inverse gamma distribution.

Usage

dinvgamma(x, shape, rate, logscale = FALSE)
pinvgamma(x, shape, rate, lower.tail = TRUE, logscale = FALSE)
qinvgamma(p, shape, rate, lower.tail = TRUE, logscale = FALSE)
rinvgamma(n, shape, rate)

Arguments

x

A vector of deviates where the density or distribution function is to be evaluated.

p

A vector of probabilities representing CDF values (if lower.tail == TRUE) or survivor function values (if lower.tail == FALSE) from the inverse gamma distribution.

n

The desired number of draws from the inverse gamma distribution.

shape

The shape parameter.

rate

The 'rate' parameter. NOTE: The term 'rate' is used to match the corresponding parameter in rgamma. Much of the rest of the world calls this the 'scale' parameter.

logscale

Logical. If TRUE then probabilities or density values are interpreted on the log scale. Otherwise the scale is the probability or probability density scale.

lower.tail

Logical. If TRUE then cumulative probabilities are measured from zero, as in a CDF. If FALSE then cumulative are measured from infinity, as in a survivor function.

Value

• rinvgamma returns draws from the distribution.

• dinvgamma returns the density function.

• pinvgamma returns the cumulative distribution function (or survivor function, if lower.tail == FALSE).

• qinvgamma returns quantiles from the distribution. qinvgamma and pinvgamma are inverse functions.

Author(s)

Steven L. Scott [e-mail]