Abstract
The problem considered is that of unbiased estimation of P [X>Y] (=θ) for two independent random variables X and Y each following a two-parameter exponential distribution. We give necessary and sufficient conditions for the existence of an unbiased estimator of θ based on arbitrary sets of order statistics obtained from independent random samples from the two populations and suggest unbiased estimators in some situations where unbiased estimators exist.
Acknowledgements
The author is thankful to the referee for his helpful comments and suggestions on an earlier draft of the paper.