A transportation strategist wanted to compare the delay in the arrival of the flights across airports and seasons. The file Delay contains delay times in the arrival of 15 randomly selected flights at John F. Kennedy international airport, New York, and William P. Hobby Airport, Houston, across each of the four seasons of the year: winter, spring, summer, and fall.

a. At the 0.05 level of significance, is there evidence of a difference in the mean delay across seasons?

b. At the 0.05 level of significance, is there evidence of a difference in the variation in the mean delay across seasons?

c. What effect does your result in (b) have on the validity of the result in (a)?

d. If appropriate, determine which seasons differ in mean delay.