A manufacturer of silk inspects each bolt of material at the end of the manufacturing process.When the process is in control,it averages 11 defects per bolt.If a 2-sigma control limit is used,what should be done if a bolt is found with 3 defects?
A) Do nothing; the process is in control.
B) Do nothing, even though the process is out of control.
C) Management should investigate and exploit the common causes of variation present.
D) Management should investigate and exploit the assignable causes of variation present.

Question

Quizplus · Accepted Answer

A 2-sigma control limit means that the process is expected to be in control 99.73% of the time. If a bolt is found with 3 defects, it is beyond the control limit, indicating that there may be an assignable cause of variation present. Therefore, management should investigate and exploit the assignable causes of variation present.

A Manufacturer of Silk Inspects Each Bolt of Material at the End