A random sample of 30 airline flights during a storm had an average delay of 40 minutes. The standard deviation was 5 minutes. Calculate a 98% confidence interval for the average delay for all flights during a storm.
A) (37.8, 42.2)
B) (38.2, 41.8)
C) (27.7, 52.3)
D) None of the above

Question

Quizplus · Accepted Answer

The correct answer is A because the confidence interval is calculated as (40 - 2.326 * 5/sqrt(30), 40 + 2.326 * 5/sqrt(30)) = (37.8, 42.2).

A Random Sample of 30 Airline Flights During a Storm