1. Explain in your own words why this is an effective guideline for SPC (Statistical Process Control).
DETECTION RULE ONE: a lack of control is indicated whenever a single point falls out-side the (three sigma) control limits.
DETECTION RULE TWO: a lack of control is indicated whenever at least two out of three successive values fall on the same side of, and more than two sigma units away from, the central line.
DETECTION RULE THREE: a lack of control is indicated whenever at least four of five successive values fall on the same side of, and more than one sigma unit away from, the central line.
DETECTION RULE FOUR: a lack of control is indicated whenever at least eight successive values fall on the same side of the central line.