Factors for calculating three-sigma limits for the x-chart and R-chart At Quick Car Wash, the wash process is advertised to take less than 6 minutes. Consequently, management has set a target average of 320 seconds for the wash process. Suppose the average range for a sample of 9 cars is 9 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 seconds and the LCLR equals seconds. (Enter your responses rounded to two decimal places.)