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|
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.
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.