Answer to Question #778 in Statistics and Probability for Valerie

Question

What is the difference between X-chart and R-chart?

Answer 1

The X-bar chart describes the changes of the mean or average over the time. It can be constructed by plotting an average value of each subgroup while R-chart is the range of each subgroup, i.e. subtraction of minimum value from the maximum one.
Usually, these charts are represented together.