This calculator finds the F-critical value once you enter the significance level (α), the numerator degrees of freedom, and the denominator degrees of freedom. Thus, instead of looking up the value from the F-distribution table, you can use this tool for accurate and instant results.
Specifically, the calculator provides the correct critical value, along with a step-by-step explanation of how to look up the value in the F-tables.
Please enter the significance level, α, numerator degrees of freedom, df1, and denominator degrees of freedom, df2, to easily find the critical F-value.
What is an F Critical Value?
If you’ve done an ANOVA test or a linear regression model before, you must be conversant with the F-test statistic. This value quantifies how much stronger your treatment effect is compared to the random noise in your data.
To determine whether the results are significant or not, you can either use a p-value approach or the classical method. The classical approach involves comparing the F-statistic value with a critical value from the F table. If the computed F-statistic value is greater than the F-critical value, we reject the null hypothesis and conclude that the results were statistically significant. Otherwise, the results were not statistically significant.
Therefore, the F-critical value statistical measure from which is compared with the computed F-statistic value to determine whether the results are significant or not.
How to Find F-Critical Value
There are several methods for finding the F-critical value. These include using a classical method, Excel method, or online F-critical value calculator.
The classical approach involves using the F-distribution table. In this case, you use a F-distribution table and look up a value that coincides with a specified significance level (α), numerator degrees of freedom (df1), and denominator degrees of freedom (df2). The resulting value is the F-critical value.
Want to learn more about how to look up the value from the F-table? Check the complete guide here.
Alternatively, you can find the critical F-value using Excel. This involves using the =F.INV.RT(alpha, df1, df2) function. You can learn more about this using our comprehensive guide on finding f-critical value using Excel.
The final method involves using the F-critical value calculator. This is the easiest, most accurate, and best approach if you’re looking for quick results. You only need to specify the significance level, numerator degrees of freedom (df1), and denominator degrees of freedom (df2). On clicking the Calculate button, the calculator instantly provides you with the critical F-value.
Finding F-Critical Value Using an Online Calculator: Solved Examples
Example 1: Suppose a teacher wants to know if the average scores of three different classes are significantly different. The significance level is 0.05, the numerator degrees of freedom are 2, and the denominator degrees of freedom are 27.
To find the critical f-value, follow these steps:
- Step1: Enter 0.05 as the significance level.
- Step 2: Enter 2 for df₁ and 27 for df₂.
- Step 3: Click the “Calculate” button.
The calculator tells you the critical value for F0.05, 2, 27 is 3.3541.
Example 2: Suppose a factory manager wants to check if three machines produce parts with different variances. The significance level is 0.01, df₁ is 2, and df₂ is 47.
To find the F-critical value using the online tool, follow these steps:
- Step 1: Enter 0.01 as the significance level.
- Step 2: Enter 2 for df₁ and 47 for df₂.
- Step 3: Click the “Calculate” button.
The calculator shows that the critical value that corresponds to F0.01, 2, 47 is 5.0874.
