A three-arm non-inferiority test for heteroscedastic data

In this paper, we consider the three-arm non-inferiority trial in the statistical testing framework established by Hida and Tango (2011). As distinct from existing methods, this paper allows the data to be heteroscedastic. Several new test statistics are developed. Numerical simulations are used to illustrate the performance of the novel proposed methods, which are compared with some existing methods. It is found that a recent proposed procedure may not control the Type I Error well when the data are heteroscedastic. Among the three new methods, the Improved Score test has the best numerical performance.