parst3: Estimate the Parameters of the 3-Parameter Student t Distribution
Description
This function estimates the parameters of the 3-parameter Student t distribution given the L-moments of the data in an L-moment object such as that returned by lmoms. The relations between distribution parameters and L-moments are seen under lmomst3. The largest value of \(\nu\) recognized is 1000, which is the Normal distribution and the smallest value recognized is 1.000001, which was arrived from manual experiments. As \(\nu \rightarrow \infty\) the distribution limits to the Cauchy, but the implementation here does not switch over to the Cauchy. Therefore in lmomco \(1.000001 \le \nu \le 1000\). The \(\nu\) is the “degrees of freedom” parameter that is well-known with the 1-parameter Student t distribution.
Usage
parst3(lmom, checklmom=TRUE, ...)
Value
An R
list is returned.
type
The type of distribution: st3.
para
The parameters of the distribution.
source
The source of the parameters: “parst3”.
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.
Author
W.H. Asquith
References
Asquith, W.H., 2011, Distributional analysis with L-moment statistics using the R environment for statistical computing: Createspace Independent Publishing Platform, ISBN 978--146350841--8.