Mohammed is monitoring the diameter of bolts being produced on one of his assigned production lines. During this process, he notices one, single measurement that jumped above the upper control limit. He immediately adjusts the alignment on several machines to address the problem. Mohammed has likely committed a(n):
A) type II error
B) average run length error
C) type I error
D) type I and type II error

Question

Quizplus · Accepted Answer

Mohammed has likely committed a type I error by adjusting the machines based on one outlier measurement without confirming if it was truly a signal of an abnormal process or just a random variation. Type II error occurs when a process is assumed to be in-control when it is actually producing nonconforming items, and average run length error refers to the average number of samples taken until a signal is detected, which is not applicable in this scenario. A type I and type II error cannot occur simultaneously.

Mohammed Is Monitoring the Diameter of Bolts Being Produced on One