114 A random sample of 225 measurements is selected from a population, and the sample mean and standard deviation are x = 32.5 and s = 30.0, respectively.

a. Use a 99% confidence interval to estimate the mean of the population, m.

b. How large a sample would be needed to estimate m to within .5 with 99% confidence?

c. What is meant by the phrase “99% confidence” as it is used in this exercise?

*d. Find a 99% confidence interval for s2.