You can use the **TINV **function in SAS to find critical values from the t distribution.

This function uses the following basic syntax:

**TINV(p, df)**

where:

**p:**1 – the significance level**df**: The degrees of freedom

The following example shows how to use the **TINV** function to find the t critical value for a left-tailed test, right-tailed test, and a two-tailed test.

**Example 1: Using TINV Function for Left-Tailed Test**

Suppose we want to find the t critical value for a left-tailed test with a significance level of .05 and degrees of freedom = 22:

We can use the **TINV **function to calculate this value:

**/*create dataset that contains t critical value*/
data my_data;
critical_val=tinv(.05, 22);
put critical_val=;
run;
/*view results*/
proc print data=my_data; **

The t critical value for a significance level of 0.05 and degrees of freedom = 22 is **-1.71714**.

Thus, if the test statistic is less than this value then the results of the test are statistically significant.

**Example 2: Using TINV Function for Right-Tailed Test**

Suppose we want to find the t critical value for a right-tailed test with a significance level of .05 and degrees of freedom = 22:

We can use the **TINV **function to calculate this value:

**/*create dataset that contains t critical value*/
data my_data;
critical_val=tinv(.95, 22);
put critical_val=;
run;
/*view results*/
proc print data=my_data; **

The t critical value for a significance level of 0.05 and degrees of freedom = 22 is **1.71714**.

Thus, if the test statistic is greater than this value then the results of the test are statistically significant.

**Example 3: Using TINV Function for Two-Tailed Test**

Suppose we want to find the t critical value for a two-tailed test with a significance level of .05 and degrees of freedom = 22:

We can use the **TINV **function to calculate this value:

**/*create dataset that contains t critical value*/
data my_data;
critical_val=tinv(.05/2, 22);
put critical_val=;
run;
/*view results*/
proc print data=my_data; **

Whenever you perform a two-tailed test, there will be two critical values. In this case, the t critical values are **-2.07387 **and **2.07387**.

Thus, if the test statistic is less than **-2.0739** or greater than **2.0739 **then the results of the test are statistically significant.

**Additional Resources**

The following tutorials explain how to perform other common tasks in SAS:

How to Perform a One Sample t-Test in SAS

How to Perform a Two Sample t-Test in SAS

How to Perform a Paired Samples t-Test in SAS