t Distribution: Critical Values of t Significance level Degrees of Two-tailed test: 10% 5% 2% 1% 0.2% 0.1% freedom One-tailed test: 5% 2.5% 1% 0.5% 0.1% 0.05% 1 6.314 12.706 31.821 63.657 318.309 636.619 2 2.920 4.303 6.965 9.925 22.327 31.599 3 2.353 3.182 4.541 5.841 10.215 12.924 4 2.132 2.776 3.747 4.604 7.173 8.610 T Table contains the critical values of the T Distribution. The column contains all the T-Distribution probabilities denoted by "Alpha" or "p". The row contains all the degrees of freedom denoted by "df". Also, here you will get one and two tail T score tables or charts online. To use this T critical value (t table) calculator, enter values in input box. The t table value calculator will instantly give you the t value for one tailed probability as well as two tailed probability. Student t-Value Calculator. In order to calculate the Student T Value for any degrees of freedom and given probability. The calculator will return Student T Values for one tail (right) and two tailed probabilities. Please input degrees of freedom and probability level and then click "CALCULATE" 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. Critical Value Calculator. Use this calculator for critical values to easily convert a significance level to its corresponding Z value, T score, F-score, or Chi-square value. Outputs the critical region as well. The tool supports one-tailed and two-tailed significance tests / probability values. It can be significantly smaller, but you weren't asking that question. That would be a one-tailed test. For a two-tailed test if the calculated value of t exceeds the tabled value, then report the p value in the table. For a one-tailed test, the p value is divided by two. So 'p . 0.05' becomes 'p 0.025." This table contains critical values of the Student's t distribution computed using the cumulative distribution function . The t distribution is symmetric so that t1-α,ν = -tα,ν . The t table can be used for both one-sided (lower and upper) and two-sided tests using the appropriate value of α . In one tailed t-tests, the critical value of t from t-distribution table represents the rejection area of distribution either left or right of the mean. In single tailed t-test, the critical value of t at a specified level of significance (α) is calculated either left side or right side of the mean of t-distribution. What critical value should be compared to the t value obtained as the test statistic? Solution: The sample size is 12. Hence the degrees of freedom ( df) = 12 - 1 = 11. Mapping the alpha level across the row for one-tailed alpha values and the df of 17 on the left-side of the table, we get our critical value as 1.363. When is T Distribution used? 8FkweV.