Note: Use excel for calculations

6. (a) The Watson Electric Company produces incandescent lightbulbs. The following data on the number of lumens for 40-watt lightbulbs were collected when the process was in control. i) Calculate control limits for R-chart and X-chart. Assume the values of A2=0.729,D4=2.282,D3= 0 . ii) Since these data were collected, some new employees were hired. A new sample obtained the following reading: 570,603,623,583. Is the process still in control? Comment