PARTIAL ORDERINGS OF LIFE DISTRIBUTIONS BASED ON AGEING PROPERTIES

Some new generalized forms of partial orderings of life distributions are introduced. Some of these orderings are based on the virtual age such as decreasing virtual ordering, new better than used virtual ordering, decreaing average virtual ordering and new better than average virtual ordering. Similar types of orderings are defmed in terms of the hazard rate. The interrelationships between these orderings are investigated and their relations with other known orderings such as the mean remaining life ordering and the global memory ordering are discussed. Some useful classes of life distributions are shown to arise when such orderings are considered with respect to the negative exponential distribution. Other related results are also discussed.