1. The average wind speed in Casper, Wyoming, has been found to 12.7 miles per hour, and in Phoenix, Arizona, it is 6.2 miles per hour. 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. Is there sufficient evidence at a _ 0.05 to conclude that the average wind speed is greater in Casper than in Phoenix? Casper Phoenix Sample size 31 31 Sample mean 12.85 mph 7.9 mph Population standard deviation 3.3 mph 2.8 mph 2. At age 9 the average weight (21.3 kg) and the average height (124.5 cm) for both boys and girls are exactly the same. A random sample of 9-year-olds yielded these results. Estimate the mean difference in height between boys and girls with 95% confidence. Does your interval support the given claim? Boys Girls Sample size 60 50 Mean height, cm 123.5 126.2 Population variance 98 120 3. A survey of 1000 students nationwide showed a mean ACT score of 21.4. A survey of 500 Ohio scores showed a mean of 20.8. If the population standard deviation in each case is 3, can we conclude that Ohio is below the national average? Use a _ 0.05