The x-bar and R-charts are best used together because sometimes an assignable cause creates no shift in the process average,or in the average value of the standard deviation,but a change occurs in the distribution of R values.

Question

Quizplus · Accepted Answer

The statement is true. Using both x-bar and R-charts together can help detect when there is a change in the distribution of R values, even if there is no shift in the process average or standard deviation. This is important because changes in variability can also indicate a problem with the process that needs to be addressed.

The X-Bar and R-Charts Are Best Used Together Because Sometimes