This article examines statistical inference for Pr(Y<X), whereXandYare independent normal variates with unknown means and variances. The case of unequal variances is stressed.Xcan be interpreted as the strength of a component subjected to a stressY, and Pr(Y<X) is the component's reliability. Two approximate methods for obtaining confidence intervals and an approximate Bayesian probability interval are obtained. The actual coverage probabilities of these intervals are examined by simulation.