An R chart is used to monitor the variation in the weights of packages of chocolate chip cookies produced by a large national producer of baked goods. An analyst has collected a baseline of 200 observations to construct the chart. Suppose the computed value of R is 3.825.

a. If subgroups of size six are to be used, compute the value of three-sigma limits for this chart.

b. If an X chart based on three-sigma limits is used, what is the difference between the UCL and LCL?