Adaptive sequential procedures for comparing new treatments with a standard

Abstract

In this paper we propose and study two sequential elimination procedures for selecting all new treatments better than a standard or control treatment. These procedures differ from those previously proposed in that we assume variances are unequal and unknown. Expressions for asymptotic expected sample sizes are given. Confidence intervals associated with the procedures are also discussed.

Keywords:

• clinical trials
• unequal and unknown variances
• triangular boundary procedures
• confidence bounds