7.89 Assessing noise levels in fitness classes.

In Exercise 7.53 (pages 394–395), you compared the noise levels in both high-intensity and low-intensity fitness classes. Suppose you are concerned with these results and want to see if the noise levels in high-intensity fitness classes in your city are above the “standard’’ level . You plan to take an SRS of classes in your neighborhood. Assuming , and the alternative mean is , what is the approximate power?