In this paper we discuss the behavlor of the statistic R^(t)
, the uniformly
minimum variance unbiased (UMVU) estimate for the reliability of gamma distribution
with unknown scale parameter σ when an outlier observation is present. Given the
outlier effect on σ, we determine bounds for the mean and mean square error (MSE) of
R(t). A semi-Bayesian approach is discussed when the outlier effect on σ
is treated
as a random variable having a prior distribution of beta type. Results of the
exponential distribution (Sinha [1]) are given as particular cases of our results.