A partial sequential t-test

Several authors have proposed sequential test procedures for testing one sided hypotheses about the mean μ of a normal distribution with unknown variance σ². Some of these procedures have concerned themselves with tests for units of (μ/σ). I this work, a sequential test procedure is introduced for hypoth-eses concerned with μ itself. In the present procedure the transformed observa-tions follow a central t-distribution as distinct from the noncentral t-distribution used in pnvious tests. Insights into properties of the operating characteristic and the average sample number functions are found for the present test; specifically, approximations to the theoretical operating characteristic function are derived and the sensitivity of the average sample number function to changes in some of the test parameters is investigated.