A certain manufacturing process has a target value of 1.20 cm and a standard deviation of 0.15 cm. A sample of nine measurements is made each hour.Is the process out of control? If so, at what hour does the mean control chart signal go out of control?

Question

Hour

Mean

1



2



3



4



5



6



Hour

Mean

7



8



9



10



11



12



Hour

Mean

13



14



15



16



17



18



Hour

Mean

19



20



21



22



23



24



  



A. The process is out of control. And, in hour 5, the value was outside the limits.

B. The process is out of control. Ten consecutive points are on one side of the target value line.

C. The process is in control.

D. The process is out of control. Two points are outside the limits.

E. The process is out of control. And, in hour 16, the value was outside the limits.

Answer 1

Answer: E