When evaluating a control chart, which of the following is not a warning

Question

signal that a random variable x is out of control? 8. __________
(a) A run of nine consecutive points on one side of the center line
(the line at target value ).
(b) One point falls beyond the 3 level.
(c) Two points fall beyond the 3 level.
(d) At least two points lie beyond the 2 level on the same side of the center line.
(e) At least two of three consecutive points lie beyond the 2 level on the same side of the center line.