blu34978_appC.

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784 Appendix C Tables

Table F The t Distribution

Confidence
intervals 80% 90% 95% 98% 99%
One tail, A 0.10 0.05 0.025 0.01 0.005
d.f. Two tails, A 0.20 0.10 0.05 0.02 0.01
1 3.078 6.314 12.706 31.821 63.657
2 1.886 2.920 4.303 6.965 9.925
3 1.638 2.353 3.182 4.541 5.841
4 1.533 2.132 2.776 3.747 4.604
5 1.476 2.015 2.571 3.365 4.032
6 1.440 1.943 2.447 3.143 3.707
7 1.415 1.895 2.365 2.998 3.499
8 1.397 1.860 2.306 2.896 3.355
9 1.383 1.833 2.262 2.821 3.250
10 1.372 1.812 2.228 2.764 3.169
11 1.363 1.796 2.201 2.718 3.106
12 1.356 1.782 2.179 2.681 3.055
13 1.350 1.771 2.160 2.650 3.012
14 1.345 1.761 2.145 2.624 2.977
15 1.341 1.753 2.131 2.602 2.947
16 1.337 1.746 2.120 2.583 2.921
17 1.333 1.740 2.110 2.567 2.898
18 1.330 1.734 2.101 2.552 2.878
19 1.328 1.729 2.093 2.539 2.861
20 1.325 1.725 2.086 2.528 2.845
21 1.323 1.721 2.080 2.518 2.831
22 1.321 1.717 2.074 2.508 2.819
23 1.319 1.714 2.069 2.500 2.807
24 1.318 1.711 2.064 2.492 2.797
25 1.316 1.708 2.060 2.485 2.787
26 1.315 1.706 2.056 2.479 2.779
27 1.314 1.703 2.052 2.473 2.771
28 1.313 1.701 2.048 2.467 2.763
29 1.311 1.699 2.045 2.462 2.756
30 1.310 1.697 2.042 2.457 2.750
32 1.309 1.694 2.037 2.449 2.738
34 1.307 1.691 2.032 2.441 2.728
36 1.306 1.688 2.028 2.434 2.719
38 1.304 1.686 2.024 2.429 2.712
40 1.303 1.684 2.021 2.423 2.704
45 1.301 1.679 2.014 2.412 2.690
50 1.299 1.676 2.009 2.403 2.678
55 1.297 1.673 2.004 2.396 2.668
60 1.296 1.671 2.000 2.390 2.660
65 1.295 1.669 1.997 2.385 2.654
70 1.294 1.667 1.994 2.381 2.648
75 1.293 1.665 1.992 2.377 2.643
80 1.292 1.664 1.990 2.374 2.639
90 1.291 1.662 1.987 2.368 2.632
100 1.290 1.660 1.984 2.364 2.626
500 1.283 1.648 1.965 2.334 2.586
1000 1.282 1.646 1.962 2.330 2.581
(z)  1.282a 1.645b 1.960 2.326c 2.576d

a
This value has been rounded to 1.28 in the textbook. One tail Two tails
b
This value has been rounded to 1.65 in the textbook.
c
This value has been rounded to 2.33 in the textbook. Area Area
d
Area
This value has been rounded to 2.58 in the textbook. ␣ ␣ ␣
2 2
Source: Adapted from W. H. Beyer, Handbook of Tables for Probability and Statistics,
2nd ed., CRC Press, Boca Raton, Fla., 1986. Reprinted with permission.
t t t

A–34