The effect of special cause variation. Is each of the following examples of a special cause most likely to first result in (i) one-point-out on the s or R chart, (ii) one-point-out on the x‾ chart, or (iii) a run on the x chart? In each case, briefly explain your reasoning.
(a) An etching solution deteriorates as more items are etched.
(b) Buildup of dirt reduces the precision with which parts are placed for machining.
(c) A new customer service representative for a Spanish-language help line is not a native speaker and has difficulty understanding customers.
(d) A data entry employee grows less attentive as his shift continues.