The U.S. air traffic control system handled an average of 47,529 flights during 30 randomly selected days. The standard deviation for this sample is 6,210 flights per day.

a. Construct a 99% confidence interval to estimate the average number of flights per day handled by the system.

b. Suppose the current system can safely handle 50,000 flights per day. What conclusions can be drawn with these results?

c. Verify this interval using Excel.

d. What assumptions need to be made about this population?

AppendixLO1