An x-bar control chart was examined and no data points fell outside of the limits. Can this process be considered in control?
A) Not yet, there could be a pattern to the points.
B) Not yet, the R-chart must be checked.
C) Not yet, the number of samples must be known.
D) Yes.
E) Both A and B

Question

Quizplus · Accepted Answer

An x-bar chart showing all points within control limits does not guarantee a process is in control. Patterns within the control limits, such as cycles or trends, can indicate a lack of control. Additionally, the R-chart (range chart) must also be checked for out-of-control signals to ensure process variability is stable.

An X-Bar Control Chart Was Examined and No Data Points