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roblem 1 Question Help * At Quickie Car Wash, the wash process is advertised to

ID: 3303218 • Letter: R

Question

roblem 1 Question Help * At Quickie Car Wash, the wash process is advertised to take less than 8 minutes. Consequently, management has set a target average of 460 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-sgma limits for the x-chart and R-chart. The UCLR equals 19.98 seconds and the LCLR equals 2.02 seconds. (Enter your responses rounded to two decimal places) The UCLi equals seconds and the La; equals seconds (Enter your responses rounded to two dec mal places)

Explanation / Answer

here for sample size n=9 ; D3 =0.184 and D4 =1.816

UCLR =D4*Ravg =1.816*11 =19.98 and   LCLR =D3*Ravg =0.184*11 =2.02

for sample size n=9 ; A2 =0.337

therefore UCLxbar =Xbar +A2*Ravg =460+0.337*11 =463.71

LCLxbar =Xbar -A2*Ravg =460-0.337*11 =456.29