Question

Which of the following statements is correct?

	a.	A mean chart monitors the variation between samples.
	b.	A range chart monitors the standard deviation resulting from common causes.
	c.	A range chart monitors the variability due to special causes.
	d.	A range chart monitors the variability due to common causes.

Answer 1

Answer 1: Correct Option – D : A range chart monitors the variability due to common causes.

This is the correct option because the Range chart is basically showing the variation in the process due to the chance/common causes.

• Range chart do not show the variation due to special causes. This can be seen in the observation chart.
• Range chart do not show the standard deviation due to chance/common causes, as it shows the variation due to chance/common cause only.
• A mean chart monitors the variation between sample means, not between samples.