12.39 Six-Sigma quality.
A process with is sometimes said to have “Six-Sigma quality.” Sketch the specification limits and a Normal distribution of individual measurements for such a process when it is properly centered. Explain from your sketch why this is called Six-Sigma quality.
12.39
It is called Six-Sigma Quality because it allows for 6 or more standard deviations on either side of the mean instead of the Normal 3 required.