This t-distribution table provides the critical t-values for both one-tailed and two-tailed t-tests, and confidence intervals. Learn how to use this t-table with the information, examples, and illustrations below the table. The t-distribution table is a table that shows the critical values of the t distribution. To use the t-distribution table, you only need to know three values: The degrees of freedom of the t-test The number of tails of the t-test (one-tailed or two-tailed) The alpha level of the t-test (common choices are 0.01, 0.05, and 0.10) The statistical tables for t and for Z provide critical values for both one- and two-tailed tests. That is, they provide the critical values that cut off an entire region at one or the other end of the sampling distribution as well as the critical values that cut off the regions (of half the size) at both ends of the sampling distribution. t-testtable.htm. Table of critical values of. t. : One Tailed Significance level: df: Two Tailed Significance level: 0.2. 0.1. If the hypothesis test is one-tailed then use the one-tailed t distribution table. Otherwise, use the two-tailed t distribution table for a two-tailed test. Match the corresponding df value (left side) and the alpha value (top row) of the table. The t table for one tail probability is given below DF ∞ 60 120 1000 = 0.1 ta = 1.282 3.078 1.886 1.638 1.533 1.476 1.440 1.415 1.397 1.383 1.372 1.363 1.356 1.350 1.345 1.341 1.337 1.333 1.330 1.328 1.325 1.323 1.321 1.319 1.318 1.316 1.315 1.314 1.313 1.311 1.310 1.296 1.289 1.282 .

one tailed critical value table