The shape of the distribution of the time required to get an oil change at a 15-minute

oil-change facility is unknown. However, records indicate that the mean time is 16.3minutes,

and the standard deviation is 3.5minutes.

A What is the probability that a random sample of n=40 oil changes results in a sample mean time less than 15 minutes?

The probability is approximately

(Round to four decimal places as needed.)

B Suppose the manager agrees to pay each employee a $50 bonus if they meet a certain goal. On a typical Saturday, the oil-change facility will perform 40 oil changes between 10 A.M. and 12 P.M. Treating this as a random sample, at what mean oil-change time would there be a 10% chance of being at or below? This will be the goal established by the manager.

There would be a 10% chance of being at or below minutes.

(Round to one decimal place as needed.)