The average wind speed in Casper, WY, has been found to be 12.7 mph, and in Phoenix, AZ, it is 6.2 mph.

To test the relationship between the averages, the average wind speed was calculated for a sample of 31 days for each city. The results are reported below. (15 pts)

Casper Phoenix Sample size n 31 31 Sample mean x 12.85 mph 7.9 mph

Population standard deviation 3.3 mph 2.8 mph Is there sufficient evidence at = 0.05 to conclude that the average wind speed is greater in Casper than in Phoenix?

Complete the hypotheses H1, a summary of your answer, and draw the normal curve.

H0: 1 = 2 = 0.05 C.V. = ________ H1: 1 2 (claim)

Supply correct symbol above