When a process is influenced only by common causes of variation,
A) the process may also be influenced by assignable causes of variation.
B) many plot points on a control chart will be outside the control limits.
C) the process is always capable of meeting customer requirements.
D) the process is in statistical control.
E) the process is never capable of meeting customer requirements.

Question

Quizplus · Accepted Answer

When a process is influenced only by common causes of variation, it means that the variation is inherent in the process and not due to any specific factors or events. In such a case, the process is said to be in statistical control, which means that it is stable and predictable over time. Therefore, the best choice is D. The other options are not correct because A is contradictory to the premise of the question, B is not necessarily true for all processes, C is not true because meeting customer requirements depends on other factors as well, and E is an extreme statement that cannot be generalized.

When a Process Is Influenced Only by Common Causes of Variation