Question

The shape of the distribution of the time required to get an oil change at a 10-minute oil-change facility is unknown.​ However, records indicate that the mean time is 11.2 minutes and the the standard deviation is 4.9 minutes. The sample size is greater than or equal to 30. Please answer C below:

What is the probability that a random sample of n=35 oil changes results in a sample mean time less than 10 minutes? The probability is approximately 0.0735

C: 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 35 oil changes between 10 a.m. and 12 p.m. Treating this as a random​ sample, there would be a​ 10% chance of the mean​ oil-change time being at or below what​ value? This will be the goal established by the manager.

There is a 10% chance of being at or below a mean oil change time of ? Minutes....please answer this. Round to 1 decimal place.

Answer 1