Quality eLine Newsletter
April 2004
Vol. 6, No. 4

Quality Quiz
from Professor Cleary

You're right!

Ben Lofen should check an SPC book, where he will discover that two points do not make a run, in anyone’s estimation. Depending on the industry, a run is typically defined as 6 to 8 data points moving in the same direction (up or down), or 6 to 8 data points above or below the mean.

As the chart indicates, a run below the mean took place between 1991 and 1997, and a run above the mean, from 1956 to 1964. If you happen to be a golf aficionado and have any clues about the causes of these runs, please email me: mike@pqsystems.com Obviously, Ben Lofen is clueless.

Copyright 2004 PQ Systems.

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