The R$-$chart

Part $2$

A$.$

generally uses control limits set at plus or minus $2$ standard deviations of the$$ distribution, rather than plus or minus$3,$ which is commonly used on the x$-$bar chart.

B$.$

is used to measure changes in the central tendency.

C$.$

is used to indicate gains or losses in dispersion.

D$.$

control limits are computed using sample standard deviations.