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Akbar Asgharzadeh

Akbar Asgharzadeh

Academic rank: Professor
ORCID:
Education: PhD.
ScopusId:
Faculty: Faculty of Mathematical Sciences
Address: Department of Statistics University of Mazandaran Babolsar, IRAN
Phone: 011-54302476

Research

Title
Approximate MLEs for the location and scale parameters of the skew logistic distribution
Type
JournalPaper
Keywords
Maximum-likelihood estimator · Monte Carlo simulation · Pivotal quantity · Skew logistic distribution
Year
2013
Journal Statistical Papers
DOI
Researchers Akbar Asgharzadeh ، Laila Esmaeili ، Saralees Nadarajah

Abstract

Azzalini (Scand J Stat 12:171–178, 1985) provided a methodology to introduce skewness in a normal distribution. Using the same method of Azzalini (1985), the skew logistic distribution can be easily obtained by introducing skewness to the logistic distribution. For the skew logistic distribution, the likelihood equations do not provide explicit solutions for the location and scale parameters. We present a simple method of deriving explicit estimators by approximating the likelihood equations appropriately. We examine numerically the bias and variance of these estimators and show that these estimators are as efficient as the maximum likelihood estimators (MLEs). The coverage probabilities of the pivotal quantities (for location and scale parameters) based on asymptotic normality are shown to be unsatisfactory, especially when the effective sample size is small. To improve the coverage probabilities and for constructing confidence intervals, we suggest the use of simulated percentage points. Finally, we present a numerical example to illustrate the methods of inference developed here