Table MOT1. Paired t test for difference in means

Computed using t and non-central t distributions; the non-centrality parameter is δ(sqrt(n)) where δ is defined in the table row title. See nQuery Advisor® manual Appendix for details of computing method for t. Figure MOT1 shows computations for one example. Additional values tested: significance level .001, .20 one and two-sided by power of 50% and 99% and effect size of .05 and 6 to n, values of n equal to 6 and 2000 and effect sizes of .05 and 6 back to power. Checked against tables in Machin D, Campbell MJ (1987) Statistical Tables for the Design of Clinical Trials, Blackwell Scientific Publications Oxford, and DOS software Stat-Power version 2.0 by Bavry JL (1991) Scientific Software, Inc and Statistical System Power Analysis by Hintze JL (1991) BMDP Statistical Software.

Figure MOT1. In the first column, nQuery Advisor® 7.0 has computed n, in the second column power, and in the third column effect size.