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12.1: Critical Values for t-Interval
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Degrees of Freedom (
df
)
|
80%
|
90%
|
95%
|
98%
|
99%
|
|
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
|
.1761
|
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
|
|
31
|
1.309
|
1.696
|
2.040
|
2.453
|
2.744
|
|
32
|
1.309
|
1.694
|
2.037
|
2.449
|
2.738
|
|
33
|
1.308
|
1.692
|
2.035
|
2.445
|
2.733
|
|
34
|
1.307
|
1.691
|
2.032
|
2.441
|
2.728
|
|
35
|
1.306
|
1.690
|
2.030
|
2.438
|
2.724
|
|
36
|
1.306
|
1.688
|
2.028
|
2.434
|
2.719
|
|
37
|
1.305
|
1.687
|
2.026
|
2.431
|
2.715
|
|
38
|
1.304
|
1.686
|
2.024
|
2.429
|
2.712
|
|
39
|
1.304
|
1.685
|
2.023
|
2.426
|
2.712
|
|
40
|
1.303
|
1.684
|
2.021
|
2.423
|
2.704
|
|
41
|
1.303
|
1.683
|
2.020
|
2.421
|
2.701
|
|
42
|
1.302
|
1.682
|
2.018
|
2.418
|
2.698
|
|
43
|
1.302
|
1.681
|
2.017
|
2.416
|
2.695
|
|
44
|
1.301
|
1.680
|
2.015
|
2.414
|
2.692
|
|
45
|
1.301
|
1.679
|
2.014
|
2.412
|
2.690
|
|
46
|
1.300
|
1.679
|
2.013
|
2.410
|
2.687
|
|
47
|
1.300
|
1.678
|
2.012
|
2.408
|
2.685
|
|
48
|
1.299
|
1.677
|
2.011
|
2.407
|
2.682
|
|
49
|
1.299
|
1.677
|
2.010
|
2.405
|
2.680
|
|
50
|
1.299
|
1.676
|
2.009
|
2.403
|
2.678
|
|
51
|
1.298
|
1.675
|
2.008
|
2.402
|
2.676
|
|
52
|
1.298
|
1.675
|
2.007
|
2.400
|
2.674
|
|
53
|
1.298
|
1.674
|
2.006
|
2.399
|
2.672
|
|
54
|
1.297
|
1.674
|
2.005
|
2.397
|
2.670
|
|
55
|
1.297
|
1.673
|
2.004
|
2.396
|
2.668
|
|
56
|
1.297
|
1.673
|
2.003
|
2.395
|
2.667
|
|
57
|
1.297
|
1.672
|
2.002
|
2.394
|
2.665
|
|
58
|
1.296
|
1.672
|
2.002
|
2.392
|
2.663
|
|
59
|
1.296
|
1.671
|
2.001
|
2.391
|
2.662
|
|
60
|
1.296
|
1.671
|
2.000
|
2.390
|
2.660
|
|
61
|
1.296
|
1.670
|
2.000
|
2.389
|
2.659
|
|
62
|
1.295
|
1.670
|
1.999
|
2.388
|
2.657
|
|
63
|
1.295
|
1.669
|
1.998
|
2.387
|
2.656
|
|
64
|
1.295
|
1.669
|
1.998
|
2.386
|
2.655
|
|
65
|
1.295
|
1.669
|
1.997
|
2.385
|
2.654
|
|
66
|
1.295
|
1.668
|
1.997
|
2.384
|
2.652
|
|
67
|
1.294
|
1.668
|
1.996
|
2.383
|
2.651
|
|
68
|
1.294
|
1.668
|
1.995
|
2.382
|
2.650
|
|
69
|
1.294
|
1.667
|
1.995
|
2.382
|
2.649
|
|
70
|
1.294
|
1.667
|
1.994
|
2.381
|
2.648
|
|
71
|
1.294
|
1.667
|
1.994
|
2.380
|
2.647
|
|
72
|
1.293
|
1.666
|
1.993
|
2.379
|
2.646
|
|
73
|
1.293
|
1.666
|
1.993
|
2.379
|
2.645
|
|
74
|
1.293
|
1.666
|
1.993
|
2.378
|
2.644
|
|
75
|
1.293
|
1.665
|
1.992
|
2.377
|
2.643
|
|
76
|
1.293
|
1.665
|
1.992
|
2.376
|
2.642
|
|
77
|
1.293
|
1.665
|
1.991
|
2.376
|
2.641
|
|
78
|
1.292
|
1.665
|
1.991
|
2.375
|
2.640
|
|
79
|
1.292
|
1.664
|
1.990
|
2.374
|
2.640
|
|
80
|
1.292
|
1.664
|
1.990
|
2.374
|
2.639
|
|
81
|
1.292
|
1.664
|
1.990
|
2.373
|
2.638
|
|
82
|
1.292
|
1.664
|
1.989
|
2.373
|
2.637
|
|
83
|
1.292
|
1.663
|
1.989
|
2.372
|
2.636
|
|
84
|
1.292
|
1.663
|
1.989
|
2.372
|
2.636
|
|
85
|
1.292
|
1.663
|
1.988
|
2.371
|
2.635
|
|
86
|
1.291
|
1.663
|
1.988
|
2.370
|
2.634
|
|
87
|
1.291
|
1.663
|
1.988
|
2.370
|
2.634
|
|
88
|
1.291
|
1.662
|
1.987
|
2.369
|
2.633
|
|
89
|
1.291
|
1.662
|
1.987
|
2.369
|
2.632
|
|
90
|
1.291
|
1.662
|
1.987
|
2.368
|
2.632
|
|
91
|
1.291
|
1.662
|
1.986
|
2.368
|
2.631
|
|
92
|
1.291
|
1.662
|
1.986
|
2.368
|
2.630
|
|
93
|
1.291
|
1.661
|
1.986
|
2.367
|
2.630
|
|
94
|
1.291
|
1.661
|
1.986
|
2.367
|
2.629
|
|
95
|
1.291
|
1.661
|
1.985
|
2.366
|
2.629
|
|
96
|
1.290
|
1.661
|
1.985
|
2.366
|
2.628
|
|
97
|
1.290
|
1.661
|
1.985
|
2.365
|
2.627
|
|
98
|
1.290
|
1.661
|
1.984
|
2.365
|
2.627
|
|
99
|
1.290
|
1.660
|
1.984
|
2.365
|
2.626
|
|
100
|
1.290
|
1.660
|
1.984
|
2.364
|
2.626
|
|
101
|
1.290
|
1.660
|
1.984
|
2.364
|
2.625
|
|
102
|
1.290
|
1.660
|
1.983
|
2.363
|
2.625
|
|
103
|
1.290
|
1.660
|
1.983
|
2.363
|
2.624
|
|
104
|
1.290
|
1.660
|
1.983
|
2.363
|
2.624
|
|
105
|
1.290
|
1.659
|
1.983
|
2.362
|
2.623
|
Table A.2: Critical Values for t-Interval