Hypothesis Test for Two Variances:

  • When to use it: To test if the variances of two populations are equal

For more information about Hypothesis Test for Two Variances click here.


F-Test Example in Excel

Let's compare certain engine head dimensions from two different production lines. A sample of 10 items was taken from line 1 and a sample of 12 items was taken from line 2.

Line 1 Line 2
415.20 415.23
415.20 415.24
415.23 415.18
415.16 415.24
415.22 415.24
415.15 415.16
415.23 415.15
415.18 415.22
415.19 415.22
415.20 415.16

We will use Excel to perform a hypothesis test of equal variances of the two lines using α = 0.05 and assuming the samples come from normal distributions.


Using Excel

Select Data, Data Analysis, F-test Two-sample for Variances. Enter the appropriate range inputs, and then click OK.


Excel should calculate the following:


Since 0.233 = p-value > \( \alpha \) = 0.05 the equality of the two variances is not rejected.


Running a two sample F test:


Do it yourself

Step 1: Go to "Attachments" on the bottom of this page and dowload the Excel spreadsheet.

Step 2: Follow the steps teached in the video above and solve the exercises in the Excel spredsheet dowloaded. 

Step 3: Answer the questions in the Interactive Content below.