Six Sigma and Beyond: Statistics and Probability, Volume III

Engineering experiments often produce responses that may not appear normal, however, many of these responses can often be transformed into normally distributed representations.

The normal distribution is emphasized because many techniques in statistics are based on the assumption of a normal distribution. Two very typical transformations are Y = In X and Y = . However, there are many more.

It is important to recognize that many seemingly nonnormal distributions can be mathematically transformed into what appears to be a normal distribution.

A useful normalization is based on the assumption of a large number of basic measurements or observations as well as the use of the Central Limit Theorem.