Appendix Table B


Table B.  Distribution of t (two tailed)
  Probability
d.f. 0.5 0.1 0.05 0.02 0.01 0.00l
             
1 l.000 6.314 12.706 3l.821 63.657 636.6l9
2 0.816 2.920 4.303 6.965 9.925 31.598
3 0.765 2.353 3.182 4.541 5.841 12.941
4 0.741 2.132 2.776 3.747 4.604 8.610
5 0.727 2.015 2.571 3.365 4.032 6.859
             
6 0.718 1.943 2.447 3.l43 3.707 5.959
7 0.711 1.895 2.365 2.998 3.499 5.405
8 0.706 l.860 2.306 2.896 3.355 5.04l
9 0.703 l.833 2.262 2.82l 3.250 4.78l
10 0.700 l.812 2.228 2.764 3.169 4.587
             
11 0.697 1.796 2.201 2.718 3.l06 4.437
12 0.695 1.782 2.179 2.681 3.055 4.3l8
13 0.694 1.771 2.160 2.650 3.012 4.221
14 0.692 1.76l 2.145 2.624 2.977 4.l40
15 0.69l l.753 2.13l 2.602 2.947 4.073
             
16 0.690 1.746 2.120 2.583 2.92l 4.015
17 0.689 1.740 2.110 2.567 2.898 3.965
18 0.688 1.734 2.101 2.552 2.878 3.922
19 0.688 l.729 2.093 2.539 2.861 3.883
20 0.687 1.725 2.086 2.528 2.845 3.850
             
21 0.686 1.721 2.080 2.518 2.831 3.8l9
22 0.686 1.717 2.074 2.508 2.819 3.792
23 0.685 1.714 2.069 2.500 2.807 3.767
24 0.685 1.711 2.064 2.492 2.797 3.745
25 0.684 1.708 2.060 2.485 2.787 3.725
             
26 0.684 1.706 2.056 2.479 2.779 3.707
27 0.684 1.703 2.052 2.473 2.771 3.690
28 0.683 1.701 2.048 2.467 2.763 3.674
29 0.683 1.699 2.045 2.462 2.756 3.659
30 0.683 l.697 2.042 2.457 2.750 3.646
             
40 0.681 l.684 2.021 2.423 2.704 3.551
60 0.679 1.671 2.000 2.390 2.660 3.460
120 0.677 1.658 l.980 2.358 2.617 3.373
  0.674 1.645 1.960 2.326 2.576 3.291

Adapted by permission of the authors and publishers from Table III of Fisher and Yates: Statistical Tables for Biological, Agricultural and Medical Research , published by Longman Group Ltd., London (previously published by Oliver & Boyd, Edinburgh).