Appendix A to Subpart B of Part 429—Student's t-Distribution Values for Certification Testing

Figure 1—t-Distribution Values for Certification Testing

[One-Sided]

Degrees of freedom (from Appendix A)	Confidence Interval				90%	95%	97.5%	99%	1	3.078	6.314	12.71	31.82	2	1.886	2.920	4.303	6.965	3	1.638	2.353	3.182	4.541	4	1.533	2.132	2.776	3.747	5	1.476	2.015	2.571	3.365	6	1.440	1.943	2.447	3.143	7	1.415	1.895	2.365	2.998	8	1.397	1.860	2.306	2.896	9	1.383	1.833	2.262	2.821	10	1.372	1.812	2.228	2.764	11	1.363	1.796	2.201	2.718	12	1.356	1.782	2.179	2.681	13	1.350	1.771	2.160	2.650	14	1.345	1.761	2.145	2.624	15	1.341	1.753	2.131	2.602	16	1.337	1.746	2.120	2.583	17	1.333	1.740	2.110	2.567	18	1.330	1.734	2.101	2.552	19	1.328	1.729	2.093	2.539	20	1.325	1.725	2.086	2.528

[76 FR 12451, Mar. 7, 2011; 76 FR 24780, May 2, 2011]