Princess Cruises offered a 9-day voyage from Beijing to Bangkok during the time period from May to August. The announced price, excluding airfare, for a room with an ocean view or a balcony was listed as

$3,475. Cruise fares usually are quite variable due to discounting by the cruise line and travel agents. A sample of 20 passengers who purchased this cruise paid the following amounts (in dollars):

3,559 3,005 3,389 3,505 3,605 3,545 3,529 3,709 3,229 3,419 3,439 3,375 3,349 3,559 3,419 3,569 3,559 3,575 3,449 3,119

a. Calculate the sample mean cruise fare.

b. Determine the sampling error for this sample.

c. Would the results obtained in part b indicate that the average cruise fare during this period for this cruise is different from the listed price? Explain your answer from a statistical point of view.