Chapter 25, Problem 10E

To determine

To explain why this happened.

Explanation of Solution

In this question in order to select the site for an electricity generating wind turbine, wind speeds were recorded at several potential sites every six hours for a year. Thus two sites not far away from each other looked good and each had a mean wind speed high enough to qualify but we should choose the site with a higher average daily wind speed. Thus the result of the statistics came out to be wrong and also the Pythagorean Theorem of statistics did not work for this case. This is because if he adds the variances the variables have to be independent. The wind speeds were recorded at nearby sites so they are likely to be high or low at the same time.