Beta exponentiated weibull distribution (Its shape and other salient characteristics)

The five–parameter beta exponentiated weibull distribution (bewd) is a versatile distribution in modelling lifetimes of various industrial products. its density curve,and so the hazard curve,has different shapes depending on the values of its parameters. in this paper we determine restrictions on the bewd parameters,and so find the associated parameter subspaces that broadly generate distinct patterns of its hazard curve. the members of each bewd subfamily that is based on a parameter subspace,display similarity of their hazard curves. using a sample hazard curve,and so the knowledge of related parameter subspace,we find estimates of the bewd parameters for fitting this distribution. it is found that these estimates are more efficient relative to those when this knowledge is not used. real data applications of bewd fitting are given using this approach. some useful properties of bewd are also found which include identification of its members that approximately behave as a normal distribution. © 2016 pakistan journal of statistics.