The shape of the distribution of the time required to get an oil change at a 20-minute oil-change facility
is unknown. However, records indicate that the mean time is 21.7 minutes, and the standard deviation is 4.6 minutes.
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 45 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?
There would be a 10% chance of being at or below ____ minutes.