Question

A national air traffic control system handled an average of 47,915 flights during 28 randomly selected days in a recent year. The standard deviation for this sample is 6,402 flights per day. Complete parts a through c below.

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

The 99​% confidence interval to estimate the average number of flights per day handled by the system is from a lower limit of to an upper limit of . ​(Round to the nearest whole​ numbers.)

b. Suppose an airline company claimed that the national air traffic control system handles an average of​ 50,000 flights per day. Do the results from this sample validate the airline​ company's claim?

A. Since the 99​% confidence interval contains​ 50,000, it can be said with 99​% confidence that the sample validates the airline​ company's claim.

B. Since the 99​% confidence interval does not contain​ 50,000, it can be said with 99​% confidence that the sample validates the airline​ company's claim.

C. Since the 99​% confidence interval contains​ 50,000, it cannot be said with 99​% confidence that the sample validates the airline​ company's claim.

D. Since the 99​% confidence interval does not contain​ 50,000, it cannot be said with 99​% confidence that the sample validates the airline​ company's claim.

c. What assumptions need to be made about this​ population?

A. Since the sample size is not greater than or equal to​ 30, one needs to assume that the population distribution is skewed to one side.

B. Since the sample size is not greater than or equal to​ 30, one needs to assume that the population distribution is not very skewed to one side.

C. Since the sample size is not greater than or equal to​ 30, one needs to assume that the population follows the​ Student's t-distribution.

D. Since the sample size is not greater than or equal to​ 30, one needs to assume that the population follows the normal probability distribution.

Answer 1