Statistical inference for the common mean of two log-normal distributions and some applications in reliability

The statistical analysis for comparing the means of two independent log-normal distributions is often of interest in biomedical research. In this paper, we present a score test for testing the equality of the means of two independent log-normal populations and compare it with that of Zhou et al. [1997. Methods for comparing means of two independent log-normal samples. Biometrics 53, 1129-1135] test in terms of their type I error rate and power. Assuming that the two means are the same, we develop procedures for estimating the common mean and investigate the performance of the resulting confidence intervals. Finally, an estimate of the reliability in the strength-stress model, is developed and the performance of the procedure is evaluated by means of simulation studies. Illustrative examples are also provided. (C) 2005 Elsevier B.V. All rights reserved.