Question

From long experience, it is known that the time it takes to do an oil change and lubrication job on a vehicle has a normal distribution with a mean of 17.8 minutes and a standard deviation of 5.2 minutes. An auto service shop will give a free lube and oil change service to any customer who must wait beyond the guaranteed time to complete the work. If the shop does not want to give more than 1% of its customers a free lube and oil change service, how long should the guarantee be? Round appropriately to the minute.

Answer 1

To find the guarantee time for an oil change and lubrication job, calculate the z-score for the 1% percentile of a standard normal distribution and use the formula z = (x - μ) / σ to solve for x. Round x to the nearest whole number.

Step-by-step explanation:

The question is asking for the guarantee time that an auto service shop should offer for an oil change and lubrication job. To find this, we need to calculate the z-score that corresponds to the 1% percentile of a standard normal distribution. The z-score can be found using a z-table or calculator, and then we can use the formula z = (x - μ) / σ to solve for x. Round x to the nearest whole number to get the guarantee time.

Answer 2

7 minutes is the answer i think but dont quote me on that