Question 66

Common cause of variation is considered a random cause that cannot be identified.

Common cause of variation refers to the inherent variability in a process that is due to random factors and cannot be traced to a specific source. This type of variation is expected in any process and is typically stable over time, making it challenging to identify and eliminate.

A) Assignable cause of variation

Assignable causes of variation are specific, identifiable sources of variation that can be traced back to a particular change or event. Since these causes can be identified and addressed, they do not fall under the category of random causes that cannot be identified.

B) Structural variation

Structural variation usually refers to changes in a system or process that are due to its design or configuration. This type of variation is also identifiable and can be altered, distinguishing it from the concept of random causes that remain undetected.

C) Common cause of variation

Common cause of variation is the term used to describe the random variability present in a process that cannot be pinpointed to any specific cause. This type of variation is inherent and often reflects the normal functioning of a system, making it the correct answer to the question.

D) Tampering

Tampering refers to unnecessary adjustments or changes made to a process in response to variations, often leading to increased variability rather than resolving it. Since tampering is an identifiable behavior rather than a random cause, it does not qualify as a random cause that cannot be identified.

Conclusion

Common cause of variation is definitively the correct answer because it encapsulates the concept of random, unidentifiable causes within a process. In contrast, all other options represent causes or behaviors that can be identified and managed, thereby failing to meet the criteria outlined in the question. Understanding these distinctions is crucial in process improvement and quality management.