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]