L-moments and TL-moments of the generalized lambda distribution
The 4-parameter generalized lambda distribution (GLD) is a flexible distribution capable of mimicking the shapes of many distributions and data samples including those with heavy tails. The method of L-moments and the recently developed method of trimmed L-moments (TL-moments) are attractive techniques for parameter estimation for heavy-tailed distributions for which the L- and TL-moments have been defined. Analytical solutions for the first five L- and TL-moments in terms of GLD parameters are derived. Unfortunately, numerical methods are needed to compute the parameters from the L- or TL-moments. Algorithms are suggested for parameter estimation. Application of the GLD using both L- and TL-moment parameter estimates from example data is demonstrated, and comparison of the L-moment fit of the 4-parameter kappa distribution is made. A small simulation study of the 98th percentile (far-right tail) is conducted for a heavy-tail GLD with high-outlier contamination. The simulations show, with respect to estimation of the 98th-percent quantile, that TL-moments are less biased (more robost) in the presence of high-outlier contamination. However, the robustness comes at the expense of considerably more sampling variability. ?? 2006 Elsevier B.V. All rights reserved.
Citation Information
Publication Year | 2007 |
---|---|
Title | L-moments and TL-moments of the generalized lambda distribution |
DOI | 10.1016/j.csda.2006.07.016 |
Authors | W.H. Asquith |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Computational Statistics and Data Analysis |
Index ID | 70029785 |
Record Source | USGS Publications Warehouse |