4. A machine for bagging hard candy will drop at least one more piece into a bag if the contents weigh 8 ounces or less. Twenty-five samples of size n = 4 were taken, and the following sums were calculated: 2X = 205.513 and XR = 2.325 ounces.

a. Establish 30 control limits for X. ;

b. Establish 30 control limits for R.