| Fisk {VGAM} | R Documentation |
Density, distribution function, quantile function and random
generation for the Fisk distribution with shape parameter a
and scale parameter scale.
dfisk(x, a, scale) pfisk(q, a, scale) qfisk(p, a, scale) rfisk(n, a, scale)
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. |
See fisk, which is the VGAM family function
for estimating the parameters by maximum likelihood estimation.
dfisk gives the density,
pfisk gives the distribution function,
qfisk gives the quantile function, and
rfisk generates random deviates.
The Fisk distribution is a special case of the 4-parameter generalized beta II distribution.
T. W. Yee
Kleiber, C. and Kotz, S. (2003) Statistical Size Distributions in Economics and Actuarial Sciences, Hoboken, NJ: Wiley-Interscience.
y = rfisk(n=1000, 4, 6) fit = vglm(y ~ 1, fisk, trace=TRUE, crit="c") coef(fit, mat=TRUE) Coef(fit)