A car mechanic is thinking of guaranteeing customers that an oil change will take no more than 15 minutes with a 99.73% confidence level.He takes a few samples of size 5 and finds the process mean to be 13 minutes with a standard deviation of .2 minutes and average sample range of 1.2 minutes.Find the , ,and values and use them to compute the upper and lower limits for an x-bar chart.Use the upper limit to determine if the mechanic can offer a 15 minute guarantee.Assume the mechanic plots the samples on the x-bar control chart and finds the process is in control,is there anything else the mechanic is missing to ensure the process is in control?

Question

A car mechanic is thinking of guaranteeing customers that an oil change will take no more than 15 minutes with a 99.73% confidence level.He takes a few samples of size 5 and finds the process mean to be 13 minutes with a standard deviation of .2 minutes and average sample range of 1.2 minutes.Find the  ,  ,and  values and use them to compute the upper and lower limits for an x-bar chart.Use the upper limit to determine if the mechanic can offer a 15 minute guarantee.Assume the mechanic plots the samples on the x-bar control chart and finds the process is in control,is there anything else the mechanic is missing to ensure the process is in control?

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The Answer of A car mechanic is thinking of guaranteeing customers that an oil change will take no more than 15 minutes with a 99.73% confidence level.He takes a few samples of size 5 and finds the process mean to be 13 minutes with a standard deviation of .2 minutes and average sample range of 1.2 minutes.Find the  ,  ,and  values and use them to compute the upper and lower limits for an x-bar chart.Use the upper limit to determine if the mechanic can offer a 15 minute guarantee.Assume the mechanic plots the samples on the x-bar control chart and finds the process is in control,is there anything else the mechanic is missing to ensure the process is in control?

A Car Mechanic Is Thinking of Guaranteeing Customers That an Oil