Table MTE1co. t-tests (TOST) of equivalence in means for crossover designs (equal n’s)

This sample size table is for the two one-sided t-test (TOST) procedure used in a crossover design for a test of the null hypothesis that the means are not equivalent (i.e. that the test drug mean differs from the standard drug mean by an amount ΔL or more in one direction or ΔU or more in the other direction). The alternative hypothesis is that the means are equivalent, defined as differing by the amount μT – μS (usually 0). Computed using bivariate non-central t distribution; the non-centrality parameters are defined in the Manual Appendix and Help. See nQuery Advisor® manual Appendix for details of the computing methods. Figure MTE1co shows computations for two examples taken from Phillips. Checked against results using MTE0 and tables and figures in Phillips, K.E. “Power of the two one-sided tests procedure in bioequivalence” Journal of Pharmacokinetics and Biopharmaceutics 18(1990) pp. 137-143. Additional values tested: significance level .001, .20 one-sided by power of 50% and 99% and very small and very large effect sizes to n, values of n equal to 3 and 2000 and small and large effect sizes back to power.

Figure MTE1co. In the first two columns, nQuery Advisor® 7.0 has solved for n and in the third and fourth columns for power.