The time it takes a mechanic to tune an engine is known to be normally distributed with a mean of 45 minutes and a standard deviation of 14 minutes.
a. Determine the mean and standard error of a sampling distribution for a sample size of 20 tune-ups. Draw a picture of the sampling distribution.
b. Calculate the largest sampling error you would expect to make in estimating the population mean with the sample size of 20 tune-ups.