Indifference-zone subset selection procedures: Using sample means to improve efficiency

Two-stage selection procedures have been widely studied and applied in determining the required sample size (i.e., the number of replications or batches) for selecting the best of k systems and for selecting a subset. The enhanced two-stage selection procedure is a heuristic two-stage selection procedure that takes into account not only the variance of samples, but also the difference of sample means when determining the sample sizes. This paper discusses the use of the same technique to select a subset of size m that contains at least c of the v best of k systems. Numerical experiments indicate that the proposed sample size allocation strategy is superior to other methods in the literature.