why do most measurement control situations include a r-chart along with the x-bar chart? group of answer choices it is important to measure and understand variability within a sample along with the sample averages. the r-chart is another way of measuring x-bar, so this turns out to be an extra check on the control of the sample averages. the r-chart is easier to calculate, so it is a way to be sure the worker doesn't make a mistake. the ups and downs of the x-bar chart should exactly match the ups and downs of the r-chart; if not, the process is out of control. none of the above is a correct answer.