Consider the control chart shown here Does the pattern appea

Consider the control chart shown here. Does the pattern appear random? Would the use of warning limits reveal any potential out of-control conditions? Apply Western Electric rules to the control chart in Exercise 5.17. Are any of the criteria for declaring the process out of control satisfied?

Solution

Yes the pattern appear random.

As no point is outside UCL and LCL, so warning limits does not reveal any potential out of control condition.

Point 3 (four of five consecutive points beyond the one sigma limit) is satisfied as out of last consecutive 5 points 4 points are outside one sigma limit.