lmomRFA (version 3.8)

regsamlmu: Sample L-moments of multiple data sets

Description

Computes the “unbiased” sample \(L\)-moments and \(L\)-moment ratios of multiple sets of data stored in a list or matrix. Following the paradigm of regional frequency analysis, we regard the data sets as coming from different measurement sites.

Usage

regsamlmu(x, nmom = 5, sort.data = TRUE, lcv = TRUE)

Value

An object of class regdata. It is a data frame with columns "name" and "n", containing respectively the site names and the number of non-missing data values at each site, and further columns containing the \(L\)-moments and \(L\)-moment ratios, in the order \(\ell_1\), \(t\) (or \(\ell_2\)),

\(t_3\), \(t_4\), etc.

Arguments

x

A list of numeric vectors, or a numeric matrix.

nmom

Number of \(L\)-moments to be computed.

sort.data

Logical: whether each data set should be sorted.

lcv

Logical. If TRUE, the second \(L\)-moment will be expressed as a fraction of the mean, i.e. the computed value will be the sample \(L\)-CV \(t=\ell_2/\ell_1\). If FALSE, the second \(L\)-moment will simply be the sample \(L\)-scale value \(\ell_2\).

Author

J. R. M. Hosking

Details

Sample \(L\)-moments are computed for each data set. The calculations use samlmu internally. If x is a list, each list element should contain data for one site and the names of the list elements should be the site names. If x is a matrix, each column should contain data for one site and the column names should be the site names.

References

Hosking, J. R. M., and Wallis, J. R. (1997). Regional frequency analysis: an approach based on \(L\)-moments. Cambridge University Press.

Examples

data(Maxwind)       # a list
regsamlmu(Maxwind)

data(airquality)    # a data frame
regsamlmu(airquality[1:4])