to set up the control chart for individual observations note that the sample average cost of the 20 observation is x = 300.5 and that the average of the moving ranges of two observations is MR = 7.79 to set up the moving range chart we use D3 =0 and d4=3.267 for n=2 therefore the moving range chart has center line MR = 7.79 LCL=0 and UCL=D$MR=(3.267)7.79=25.45 the control chart (from minitab) is shown in figure 6.19b Notice that no points are out of control