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T distribution table

From OPOSSEM

This table presents the appropriate critical values of the Student's t statistic for a number of common confidence levels and degrees of freedom. To use this table, identify the column with the appropriate confidence level and then find the row with the number of degrees of freedom appropriate for the statistical test (for example, in the difference of means t test, this would be <math>n_1 + n_2 - 2</math>).

If there is no row for the exact number of degrees of freedom for your test, read the row with the number of degrees of freedom rounded down. For very large numbers of degrees of freedom (over 300 or so), it is acceptable to use the row labeled ∞, which is equivalent to the standard normal distribution (Z table).

This table is designed for use with two-tailed tests and confidence intervals. The one-tailed confidence levels presented here are 95%, 97.5%, and 99.5% respectively.

df 90% 95% 99%
1 6.314 12.706 63.657
2 2.920 4.303 9.925
3 2.353 3.182 5.841
4 2.132 2.776 4.604
5 2.015 2.571 4.032
6 1.943 2.447 3.707
7 1.895 2.365 3.499
8 1.860 2.306 3.355
9 1.833 2.262 3.250
10 1.812 2.228 3.169
11 1.796 2.201 3.106
12 1.782 2.179 3.055
13 1.771 2.160 3.012
14 1.761 2.145 2.977
15 1.753 2.131 2.947
16 1.746 2.120 2.921
17 1.740 2.110 2.898
18 1.734 2.101 2.878
19 1.729 2.093 2.861
20 1.725 2.086 2.845
21 1.721 2.080 2.831
22 1.717 2.074 2.819
23 1.714 2.069 2.807
24 1.711 2.064 2.797
25 1.708 2.060 2.787
26 1.706 2.056 2.779
27 1.703 2.052 2.771
28 1.701 2.048 2.763
29 1.699 2.045 2.756
30 1.697 2.042 2.750
31 1.696 2.040 2.744
32 1.694 2.037 2.738
33 1.692 2.035 2.733
34 1.691 2.032 2.728
35 1.690 2.030 2.724
36 1.688 2.028 2.719
37 1.687 2.026 2.715
38 1.686 2.024 2.712
39 1.685 2.023 2.708
40 1.684 2.021 2.704
50 1.676 2.009 2.678
60 1.671 2.000 2.660
70 1.667 1.994 2.648
80 1.664 1.990 2.639
90 1.662 1.987 2.632
100 1.660 1.984 2.626
110 1.659 1.982 2.621
120 1.658 1.980 2.617
200 1.653 1.972 2.601
1.645 1.960 2.576