You can use the **FINV **function in SAS to find critical values from the F distribution.

This function uses the following basic syntax:

**FINV(p, ndf, ddf)**

where:

**p:**1 – the significance level**ndf**: The numerator degrees of freedom**ddf**: The denominator degrees of freedom

The following example shows how to use the **FINV** function in practice to calculate F critical values.

**Example: How to Use FINV Function in SAS to Calculate F Critical Values**

Suppose we would like to find the F critical value for a significance level of **0.05**, numerator degrees of freedom = **6**, and denominator degrees of freedom = **8**.

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

**/*create dataset that contains F critical value*/
data my_data;
critical_val=finv(.95, 6, 8);
put critical_val=;
run;
/*view results*/
proc print data=my_data; **

The F critical value for a significance level of 0.05, numerator degrees of freedom = 6, and denominator degrees of freedom = 8 is **3.58058**.

Thus, if we’re conducting some type of F test then we can compare the F test statistic to **3.58058**.

If the F statistic is greater than **3.58058**, then the results of the test are statistically significant.

It’s worth noting that smaller values for the significance level will lead to larger F critical values.

For example, consider the F critical value for a significance level of 0.01, numerator degrees of freedom = 6, and denominator degrees of freedom = 8:

**/*create dataset that contains F critical value*/
data my_data;
critical_val=finv(.99, 6, 8);
put critical_val=;
run;
/*view results*/
proc print data=my_data; **

The F critical value for a significance level of 0.05, numerator degrees of freedom = 6, and denominator degrees of freedom = 8 is **6.37068**.

**Note**: You can also use the F distribution table to find critical values by hand. The values that you find in the table will match the ones calculated by the **FINV** function in SAS.

**Additional Resources**

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

How to Use the TINV Function in SAS

How to Use the CINV Function in SAS

How to Calculate Z-Scores in SAS