parwei: Estimate the Parameters of the Weibull Distribution

In wasquith/lmomco: L-Moments, Censored L-Moments, Trimmed L-Moments, L-Comoments, and Many Distributions

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 lmoms. 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 relations between the Generalized Extreme Value parameters (\xi, \alpha, and \kappa) and the Weibull parameters are

\kappa = 1/\delta \mbox{,}

\alpha = \beta/\delta \mbox{, and}

\xi = \zeta - \beta \mbox{.}

These relations are taken from Hosking and Wallis (1997). The relations between the distribution parameters and L-moments are seen under lmomgev.

Usage

parwei(lmom,checklmom=TRUE, ...)

Arguments

lmom	An L-moment object created by lmoms or vec2lmom.
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.
...	Other arguments to pass.

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

lmomwei, cdfwei, pdfwei, quawei

Examples

parwei(lmoms(rnorm(20)))
## Not run: 
str(parwei(lmoms(rweibull(3000,1.3, scale=340)-1200))) #
## End(Not run)

wasquith/lmomco documentation built on Nov. 13, 2024, 4:53 p.m.