Travel and Transportation
During a routine commercial airline flight, much of the time in the aircraft is spent waiting to take off and taxiing to an arrival gate. However, airlines also keep careful records of the actual air time of each flight. A random sample of the air times (in minutes) of US Airways flights from Philadelphia to Las Vegas during December 2012 was obtained, and the data are given in the following table.
The air time for this flight is affected by the prevailing west-toeast winds and weather systems and normally takes 303 minutes. Is there any evidence to suggest the true mean air time is greater than this 303 minutes? Assume the underlying distribution is normal and use a = 0.025.