Common causes of variation:
A) occur when 2 of 3 consecutive points on a statistical process control chart are above or below the center line of the chart.
B) occur when adjusting a process that is already in control.
C) generally account for 80 to 95 percent of the observed variation in a process.
D) can be prevented, explained, and easily understood.

Question

Quizplus · Accepted Answer

Common causes of variation are inherent in a process and are typically due to factors such as variation in raw materials, machine settings, worker performance, and environmental conditions. These types of variation are considered normal and expected, and account for the majority of the observed variation in a process. While they cannot be eliminated completely, they can be controlled and minimized through process improvement techniques. A and B are incorrect as they refer to special causes of variation, which are unexpected and non-random events that can cause sudden changes in a process. D is incorrect as common causes of variation cannot be completely prevented, and may not always be easily understood.

Common Causes of Variation