F-Tests Determine if Variances are the Same or Different

You Don't Have to be a Statistician to do an F-Test in Excel

QI Macros Add-in for Excel Makes F-Tests as Easy as 1-2-3

  1. Click and drag over your data to select it in Excel:
  2. example of f test data

  3. Click on the QI Macros Menu > Statistical Tools > F & t Tests, and then select "F-test: Two-sample for Variance":
  4. f-test-menu

  5. QI Macros will prompt for a significance level (default = 0.05):
  6. significance level prompt

  7. QI Macros will perform the F-Test calculations and interpret the results for you:
  8. f test calculations and results using QI Macros for Excel

What's Cool about QI Macros F-Test?

Interprets the Results for You: QI Macros compares the p value to alpha and tells you what that means. In the above example, QI Macros tells you "Cannot Reject the Null Hypothesis/Accept the Null Hypothesis," because p > 0.05 (Variances are not Different/Variances are the Same).

Interactive Results: QI Macros lets you change the significance level to see what impact those changes have on your results.

Based on the F-test results, we now know which two sample t-test to run.

F-Test Video Example

If you're producing rubber made with two different recipes, you might want to know if the variances in tensile strengths are the same or different (Juran's QC Handbook 4th pg 23.74):

Why Choose QI Macros Statistical Software for Excel?



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