Large-sample estimation of reliability under the exponential distribution in life testing

The exact formula for the variance of the uniformly minimum variance unbiased estimator (UMVUE) of the reliability function, R(t), for exponential life is quite cumbersome. A simple expression for the asymptotic variance of the UMVUE of R(t) is found. Interval estimates of R(t) are also constructed. By comparing the approximations to the exact values in several configurations of sample size and population parameter, the derived formula is shown to be useful for sample sizes larger than 15