Inference Of Two Mean Life Spans Ratio

Higher product quality is usually one of the crucial factors that make an enterprise more advantaged in the competitive markets. The rate of two expected lifetimes is an important index to judge if a newly designed product is better than its old version or a product is of longer lifetime than its competitors. In this paper, under the type- II censoring life test, we separately deduced the estimators of the rate of two expected lifetimes for the families of single parameter exponential distributions, location-scale exponential distributions, and Weibull distributions. The expectations, variances and their large sample properties are studied. Finally, we conduct small simulations for the properties of the estimators for small sample size.