Find Critical Value of t for One Tailed t-Test

Student's t-distribution table & how to use instructions to quickly find the table or critical (rejection region) value of t at a stated level of significance (α) to check if the test of hypothesis (H₀) for one (right or left) tailed t-test is accepted or rejected in statistics & probability experiments to analyze the small samples. The degrees of freedom is used to refer the t-table values at a specified level of significance such as 1%, 2%, 3%, 4%, 5%, 10%, 25%, 50% etc. It's generally represented by t_e. In one (right or left) tailed Student's t-test, the calculated value of t or t-statistic (t₀) is compared with the table or critical value of t to check if the null hypothesis is accepted or rejected in the statistical experiments include small sample size. This students's t-table for one tailed t-test is also available in pdf format too, users may download this table in pdf format to refer it later offline.

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. Whereas, in two tailed t-test, the critical value of t at a specified level of significance (α) is calculated for both left & right side of the mean of t-distribution but the α value is divided by 2 and corresponding critical value of t is derived from the t-distribution table for both halves. For example, t_0.5 of single tailed test equals to t_(0.25) of two tailed test.

In other words, a single tailed t-test at 10% significance level have the rejection area either in left or right side of the mean, while for two tailed t-test at 10% significance level have 5% rejection area on the left side & remaining 5% rejection area on the right side of the mean.