The F-distribution is another distribution that is used extensively in statistical analysis to test certain hypotheses arising from the comparison of two or more normal distributions.

Use: One of the ‘operational definitions’ of quality follows: Quality is considered the minimum deviation around a target value. We often spend a significant amount of time and money making sure our processes are ‘targeted’ appropriately, but it is just as important to assure that processes are operating as consistently (that is, with as little variation) as possible. One of the basic ideas of control charts is to use them to monitor a process so that it can be brought into a state of statistical control through the identification and elimination of special causes. Moreover, the elimination of special causes should also lead to reduce variation. But, how do we test for this? We would use the F-test.

Six Sigma Terminology