Aghababaei Jazi Mansour

IFS/Statistics, Massey University, Palmerston North

Some extensions of the geometric distribution

We shall consider some extensions of the geometric distribution which are usually used in life time distributions. The discrete Weibull distribution as a discrete analogue of the standard continuous Weibull distribution was proposed in the literature to meet the need of fitting discrete time reliability and survival data sets. Its properties were studied and methods of estimation of its parameters were also investigated by various authors. Analogous to its continuous counterpart, the discrete Weibull does not provide a good fit to data sets that exhibit non-monotonic hazard rate shapes. So, we propose a discrete inverse Weibull distribution which is a discrete version of the continuous inverse Weibull variable. Then, we shall discuss their structural properties such as modality and divisibility. It is shown that the hazard rate function can attain a unimodal or monotonely decreasing shape for certain values of parameters.