More Info 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) 2 1.880 3 1.023 4 0.729 5 0.577 6 0.483 7 0.419 8 0.373 9 0.337 10 0.308 Factor for LCL for R-Chart (D3) 0 0 0 0 0 0.076 0.136 0.184 0.223 Factor for UCL for R-Chart (D4) 3.267 2.575 2.282 2.115 2.004 1.924 1.864 1.816 1.777 At Quickie Car Wash, the wash process is advertised to take less than 8 minutes. Consequently, management has set a target average of 440 seconds for the wash process. Suppose the average range for a sample of 9 cars is 11 seconds. Use the accompanying table to establish control limits for sample means and ranges for the car wash process. Click the icon to view the table of factors for calculating three-sigma limits for the x-chart and R-chart. The UCLR equals 18.16 seconds and the LCLR equals 1.84 seconds. (Enter your responses rounded to two decimal places.)