t分布及t分布表
http://baike.baidu.com/view/1419652.htm
下表列出了自由度为1-30以及80、100、120等t-分布的单侧和双侧区间值。例如，当样本数量n=5时，则自由度v=4，我们就可以查找表中以4开头的行。该行第5列值为2.132，对应的单侧值为95%（双侧值为90%）。这也就是说，T小于2.132的概率为95%（即单侧），记为Pr(−∞ < T < 2.132) = 0.95；同时，T值介于-2.132和2.132之间的概率为90%（即双侧），记为Pr(−2.132 < T < 2.132) = 0.9。
这是根据分布的对称性计算得到的，
-
Pr(T < −2.132) = 1 − Pr(T > −2.132) = 1 − 0.95 = 0.05,
因此，
-
Pr(−2.132 < T < 2.132) = 1 − 2(0.05) = 0.9.
注意 关于表格的最后一行的值：自由度为无限大（n=120）的t-分布和正态分布等价。
|
单侧
|
75%
|
80%
|
85%
|
90%
|
95%
|
97.5%
|
99%
|
99.5%
|
99.75%
|
99.9%
|
99.95%
|
|---|---|---|---|---|---|---|---|---|---|---|---|
|
双侧
|
50%
|
60%
|
70%
|
80%
|
90%
|
95%
|
98%
|
99%
|
99.5%
|
99.8%
|
99.9%
|
|
1
|
1.000
|
1.376
|
1.963
|
3.078
|
6.314
|
12.71
|
31.82
|
63.66
|
127.3
|
318.3
|
636.6
|
|
2
|
0.816
|
1.061
|
1.386
|
1.886
|
2.920
|
4.303
|
6.965
|
9.925
|
14.09
|
22.33
|
31.60
|
|
3
|
0.765
|
0.978
|
1.250
|
1.638
|
2.353
|
3.182
|
4.541
|
5.841
|
7.453
|
10.21
|
12.92
|
|
4
|
0.741
|
0.941
|
1.190
|
1.533
|
2.132
|
2.776
|
3.747
|
4.604
|
5.598
|
7.173
|
8.610
|
|
5
|
0.727
|
0.920
|
1.156
|
1.476
|
2.015
|
2.571
|
3.365
|
4.032
|
4.773
|
5.893
|
6.869
|
|
6
|
0.718
|
0.906
|
1.134
|
1.440
|
1.943
|
2.447
|
3.143
|
3.707
|
4.317
|
5.208
|
5.959
|
|
7
|
0.711
|
0.896
|
1.119
|
1.415
|
1.895
|
2.365
|
2.998
|
3.499
|
4.029
|
4.785
|
5.408
|
|
8
|
0.706
|
0.889
|
1.108
|
1.397
|
1.860
|
2.306
|
2.896
|
3.355
|
3.833
|
4.501
|
5.041
|
|
9
|
0.703
|
0.883
|
1.100
|
1.383
|
1.833
|
2.262
|
2.821
|
3.250
|
3.690
|
4.297
|
4.781
|
|
10
|
0.700
|
0.879
|
1.093
|
1.372
|
1.812
|
2.228
|
2.764
|
3.169
|
3.581
|
4.144
|
4.587
|
|
11
|
0.697
|
0.876
|
1.088
|
1.363
|
1.796
|
2.201
|
2.718
|
3.106
|
3.497
|
4.025
|
4.437
|
|
12
|
0.695
|
0.873
|
1.083
|
1.356
|
1.782
|
2.179
|
2.681
|
3.055
|
3.428
|
3.930
|
4.318
|
|
13
|
0.694
|
0.870
|
1.079
|
1.350
|
1.771
|
2.160
|
2.650
|
3.012
|
3.372
|
3.852
|
4.221
|
|
14
|
0.692
|
0.868
|
1.076
|
1.345
|
1.761
|
2.145
|
2.624
|
2.977
|
3.326
|
3.787
|
4.140
|
|
15
|
0.691
|
0.866
|
1.074
|
1.341
|
1.753
|
2.131
|
2.602
|
2.947
|
3.286
|
3.733
|
4.073
|
|
16
|
0.690
|
0.865
|
1.071
|
1.337
|
1.746
|
2.120
|
2.583
|
2.921
|
3.252
|
3.686
|
4.015
|
|
17
|
0.689
|
0.863
|
1.069
|
1.333
|
1.740
|
2.110
|
2.567
|
2.898
|
3.222
|
3.646
|
3.965
|
|
18
|
0.688
|
0.862
|
1.067
|
1.330
|
1.734
|
2.101
|
2.552
|
2.878
|
3.197
|
3.610
|
3.922
|
|
19
|
0.688
|
0.861
|
1.066
|
1.328
|
1.729
|
2.093
|
2.539
|
2.861
|
3.174
|
3.579
|
3.883
|
|
20
|
0.687
|
0.860
|
1.064
|
1.325
|
1.725
|
2.086
|
2.528
|
2.845
|
3.153
|
3.552
|
3.850
|
|
21
|
0.686
|
0.859
|
1.063
|
1.323
|
1.721
|
2.080
|
2.518
|
2.831
|
3.135
|
3.527
|
3.819
|
|
22
|
0.686
|
0.858
|
1.061
|
1.321
|
1.717
|
2.074
|
2.508
|
2.819
|
3.119
|
3.505
|
3.792
|
|
23
|
0.685
|
0.858
|
1.060
|
1.319
|
1.714
|
2.069
|
2.500
|
2.807
|
3.104
|
3.485
|
3.767
|
|
24
|
0.685
|
0.857
|
1.059
|
1.318
|
1.711
|
2.064
|
2.492
|
2.797
|
3.091
|
3.467
|
3.745
|
|
25
|
0.684
|
0.856
|
1.058
|
1.316
|
1.708
|
2.060
|
2.485
|
2.787
|
3.078
|
3.450
|
3.725
|
|
26
|
0.684
|
0.856
|
1.058
|
1.315
|
1.706
|
2.056
|
2.479
|
2.779
|
3.067
|
3.435
|
3.707
|
|
27
|
0.684
|
0.855
|
1.057
|
1.314
|
1.703
|
2.052
|
2.473
|
2.771
|
3.057
|
3.421
|
3.690
|
|
28
|
0.683
|
0.855
|
1.056
|
1.313
|
1.701
|
2.048
|
2.467
|
2.763
|
3.047
|
3.408
|
3.674
|
|
29
|
0.683
|
0.854
|
1.055
|
1.311
|
1.699
|
2.045
|
2.462
|
2.756
|
3.038
|
3.396
|
3.659
|
|
30
|
0.683
|
0.854
|
1.055
|
1.310
|
1.697
|
2.042
|
2.457
|
2.750
|
3.030
|
3.385
|
3.646
|
|
40
|
0.681
|
0.851
|
1.050
|
1.303
|
1.684
|
2.021
|
2.423
|
2.704
|
2.971
|
3.307
|
3.551
|
|
50
|
0.679
|
0.849
|
1.047
|
1.299
|
1.676
|
2.009
|
2.403
|
2.678
|
2.937
|
3.261
|
3.496
|
|
60
|
0.679
|
0.848
|
1.045
|
1.296
|
1.671
|
2.000
|
2.390
|
2.660
|
2.915
|
3.232
|
3.460
|
|
80
|
0.678
|
0.846
|
1.043
|
1.292
|
1.664
|
1.990
|
2.374
|
2.639
|
2.887
|
3.195
|
3.416
|
|
100
|
0.677
|
0.845
|
1.042
|
1.290
|
1.660
|
1.984
|
2.364
|
2.626
|
2.871
|
3.174
|
3.390
|
|
120
|
0.677
|
0.845
|
1.041
|
1.289
|
1.658
|
1.980
|
2.358
|
2.617
|
2.860
|
3.160
|
3.373
|
|
0.674
|
0.842
|
1.036
|
1.282
|
1.645
|
1.960
|
2.326
|
2.576
|
2.807
|
3.090
|
3.291
|
