parwei {lmomco}R Documentation

Estimate the Parameters of the Weibull Distribution

Description

This function estimates the parameters of the Weibull distribution given the L-moments of the data in an L-moment object such as that returned by lmom.ub. The Weibull distribution is a reverse Generalized Extreme Value distribution. As result, the Generalized Extreme Value algorithms are used for implementation of the Weibull in this package. The relation between the Generalized Extreme Value parameters (xi, α, and kappa) is

kappa = 1/delta mbox{,}

α = β/delta mbox{, and}

xi = zeta - β mbox{.}

These relations are taken from Hosking and Wallis (1997).

Usage

parwei(lmom,checklmom=TRUE)

Arguments

lmom A L-moment object created by lmom.ub or pwm2lmom.
checklmom Should the lmom be checked for validity using the are.lmom.valid function. Normally this should be left as the default and it is very unlikely that the L-moments will not be viable (particularly in the tau_4 and tau_3 inequality). However, for some circumstances or large simulation exercises then one might want to bypass this check.

Value

An R list is returned.

type The type of distribution: wei.
para The parameters of the distribution.
source The source of the parameters: “parwei”.

Author(s)

W.H. Asquith

References

Hosking, J.R.M. and Wallis, J.R., 1997, Regional frequency analysis—An approach based on L-moments: Cambridge University Press.

See Also

lmom.ub, lmomwei, cdfwei, quawei

Examples

lmr <- lmom.ub(rnorm(20))
parwei(lmr)
lmr <- parwei(lmom.ub(rweibull(3000,1.3,scale=340)-1200))
str(lmr)


[Package lmomco version 0.96.3 Index]