Fisk {VGAM}R Documentation

The Fisk Distribution

Description

Density, distribution function, quantile function and random generation for the Fisk distribution with shape parameter a and scale parameter scale.

Usage

dfisk(x, a, scale)
pfisk(q, a, scale)
qfisk(p, a, scale)
rfisk(n, a, scale)

Arguments

x, q vector of quantiles.
p vector of probabilities.
n number of observations. If length(n) > 1, the length is taken to be the number required.
a shape parameter.
scale scale parameter.

Details

See fisk, which is the VGAM family function for estimating the parameters by maximum likelihood estimation.

Value

dfisk gives the density, pfisk gives the distribution function, qfisk gives the quantile function, and rfisk generates random deviates.

Note

The Fisk distribution is a special case of the 4-parameter generalized beta II distribution.

Author(s)

T. W. Yee

References

Kleiber, C. and Kotz, S. (2003) Statistical Size Distributions in Economics and Actuarial Sciences, Hoboken, NJ: Wiley-Interscience.

See Also

fisk, genbetaII.

Examples

y = rfisk(n=1000, 4, 6)
fit = vglm(y ~ 1, fisk, trace=TRUE, crit="c")
coef(fit, mat=TRUE)
Coef(fit)

[Package VGAM version 0.7-7 Index]