The exponentiated weibull family: some properties and a flood data application

The exponentiated Weibull family, a Weibull extension obtained by adding a second shape parameter, consists of regular distributions with bathtub shaped, unimodal and a broad variety of monotone hazard rates. It can be used for modeling lifetime data from reliability, survival and population studies, various extreme value data, and for constructing isotones of the tests of the composite hypothesis of exponentiality. The structural analysis of the family in this paper includes study of its skewness and kurtosis properties, density shapes and tail character, and the associated extreme value and extreme spacings distributions. Its usefulness in modeling extreme value data is illustrated using the floods of the Floyd River at James, Iowa.