Factors for calculating three-sigma limits for the x-chart and R-chart Size of Sample Factor for UCL and LCL (n) for X-chart (A2) Factor for LCL for R-Chart (D3) Factor for UCL for R-Chart (D4) 2 0 3 0 0 4 5 0 6 1.880 1.023 0.729 0.577 0.483 0.419 0.373 0.337 0.308 0 3.267 2.575 2.282 2.115 2.004 1.924 1.864 1.816 1.777 7 8 0.076 0.136 0.184 0.223 9 10 At Quickie Car Wash, the wash process is advertised to take less than 8 minutes. Consequently, management has set a target average of 450 seconds for the wash process. Suppose the average range for a sample of 7 cars is 11 seconds. Use the accompanying table to establish control limits for sample means and ranges for the car wash process. The UCLR equals 19.24 seconds and the LCLR equals 0.76 seconds. (Enter your responses rounded to two decimal places.) The UCL, equals seconds and the LCL; equals seconds. (Enter your responses rounded to two decimal places.)