Listed below are the costs (in dollars) of eight different flights from New York (JFK) to San Francisco for Virgin America, US Airways, United Airlines, JetBlue, Delta, American Airlines, Alaska Airlines, and Sun Country Airlines. (Each pair of costs is for the same flight.) Use the sign test to test the claim that there is no difference in cost between flights scheduled 1 day in advance and those scheduled 30 days in advance. What appears to be a wise scheduling strategy?

Use the runs test with a significance level of A = 0.05.