A company believes a process monitored by an x-bar chart to be in control.When the most recent control point exceeded the UCL value by 20%,the company should
A)believe that a random bad luck chance occurred and proceed.
B)suspect that an assignable cause of variation now exists and can be found.
C)ignore the control point completely,as it is simply an outlier.
D)wait for the next four samples to be taken to see if a trend develops.
E)All of the above

Question

Quizplus · Accepted Answer

Exceeding the UCL value by 20% indicates a signal of an assignable cause of variation, and the company should investigate to find the cause and take appropriate corrective actions. Option A is incorrect as it is important to investigate any unexpected change, and not assume it as mere bad luck. Option C is incorrect as it is important to analyze all data points and not simply ignore outliers. Option D is incorrect as waiting for the next four samples may lead to further variation and increase the cost of quality control.

A Company Believes a Process Monitored by an X-Bar Chart