Unoccupied seats on flights cause airlines to lose revenue. Suppose a large airline wants to estimate its mean number of unoccupied seats per flight over the past year. To accomplish this, the records of 225 flights are randomly selected, and the number of unoccupied seats is noted for each of the sampled flights. The sample mean is 12.4 seats, and the sample standard deviation is 4.7 seats.

a) Construct a 90% confidence interval for the population mean number of unoccupied seats per flight.

To show your work, give the calculator command and values you used:

Give the confidence interval, do not round: ( , )

b) Using the context of the problem, give an appropriate interpretation for the confidence interval you found above.