How to use the F-Test Function

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We use the F-test to decide the equality of two population variances. The F-test is also vital when carrying out the Analysis of Variance (ANOVA). In this tutorial, we will describe the F-Test function and show how we can do the F-Test in Excel.

Figure 1 – F test example

How to enable the Excel F-test

We need the Analysis ToolPak add-in to use the F-test function. We can turn this feature on in our worksheet because this add-in comes pre-installed with our Microsoft Excel application. To enable the Analysis ToolPak;

• We will go to file and then select Options

Figure 2 – How to do an f test

• In the Options dialog window, we will select Add-ins

Figure 3 – F-test in excel

• In the Add-ins dialog box, we will click Analysis Toolpak and select OK.

Figure 4 – How to do an f-test

How to do the F-test in Excel

• We will set up our data to carry out the F-test Analysis

Figure 5 – Setting data for f test chart

• Next, we will go to the Data Tab and select Data Analysis

Figure 6 – F-test using Data Analysis

• In the Data Analysis dialog box, we will click on f-test two samples for variances and select OK to enable the function

Figure 7 – F-test two sample for variances

• The F-test two samples for variances dialog box will come up.

Figure 8 – F-test in excel

• Here we will enter the range for Variable Range 1 and 2. We will do this by:
• Clicking in the input section for Variable 1 Range followed by highlighting on the range of values
• Next, we will click on the input section for Variable 2 Range followed by highlighting the range of values.

Figure 9 – F-test two sample for variances

• In the Output values section at the base of the dialog window, we will mark the output range and enter the space on our worksheet where we wish to see our results.

Figure 10 – F-test for variance

• Lastly, we will select OK. Our F-test will return with this result

Figure 11 – How to do an f test

Note

FTEST(array1,array2)

Where: array 1 is the first data range or array; array2 is the second data range or array

• Arguments must always contain numbers (even when names or numbers are included)
• If the array contains text, empty cells or logical values, then the cells will be ignored
• Cells with values zero will be included.
• If the number of data points of array1 or array2 equal zero or array 1 or array 2 is less than zero, then the F-Test will return with a #DIV/0! error value.