77
Vol.5.Issue.2.2017 (April-June)
©KY PUBLICATIONS
THE GENERALIZED WEIBULL-GUMBEL DISTRIBUTION
Innocent Boyle ERAIKHUEMEN
1
, Terna Godfrey IEREN
2
1
Department of Mathematics and Computer Science, Benson Idahosa University Benin-city, Nigeria
ieraikhuemen@biu.edu.ng
2
Department of Statistics, Ahmadu Bello University Zaria, Nigeria
ternagodfrey@gmail.com
ABSTRACT
This paper studies another generalization of the Gumbel distribution known
as the Generalized Weibull-Gumbel distribution useful for modeling lifetime
data. The mathematical properties of the new distribution are provided. The
explicit expressions for its quantile, survival, and hazard functions were
studied. Some plots of the distribution indicate that the Generalized Weibull-
Gumbel distribution can take various shapes such as symmetrical, left-
skewed, right-skewed etc. This fact implies that the Generalized Weibull-
Gumbel distribution can be very useful for data sets under various shapes.
The implications of the plots for the survival and hazard functions means that
the Generalized Weibull-Gumbel distribution (GWGD) will be appropriate in
modeling time or age-dependent events, where survival rate decreases with
time and failure increases with time or age. The method of maximum
likelihood is used for estimating the model parameters and the density
function for the minimum and maximum order statistics are also derived. We
finally illustrate the usefulness of the proposed model.
Keywords: Gumbel Distribution, Reliability analysis, Maximum likelihood
estimation, order statistics and Generalized Weibull-Gumbel distribution.
1 Background
The Gumbel distribution is a very popular statistical model due to its wide applicability. An
extensive list of the Gumbel model applications can be obtained in Kotz and Nadarajah (2000). Some
applications of the Gumbel model include: climate modeling, global warming problems, offshore
modeling, rainfall and wind speed modeling Nadarajah (2006). The applications of this model can
also be found in various areas of engineering, suĐh as flood frequency analysis, network, nuclear,
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