Table DOT2. t distribution (non-central)

See nQuery Advisor® manual Appendix for computing method. Figure DOT2 shows t-values for 6 degrees of freedom to reflect example in which two-sided alpha is .05 and power requested is .90. Additional values tested: for non-centrality of 0, degrees of freedom 1, 2, 10, 10000 and probability .001, .999 to t and those values of t back to probability, plus the paired values of probability and t back to non-centrality. For degrees of freedom 2, 100, 10000 compute t value for probability of .999 and non-centrality of 0, then change probability to .001 and compute non-centrality. Using non-centrality value and probability of .001 recompute t and then using t and non-centrality recomputed probability. Values checked against tables in Dixon WJ, Massey FJ (1983) Introduction to Statistical Analysis. 4th edition. McGraw-Hill. New York and/or StaTable. Electronic Tables for Scientists and Engineers. Version 1. 1994 Cytel Software Corporation.

Figure DOT2. In the first column, t is computed, in the second column, non-centrality is computed, in the third column t is computed, and in the fourth column probability is computed by nQuery Advisor® 7.0.