A random sample of 225 measurements is selected from a population, and the sample mean and standard deviation are = 32.5 and s = 30.0, respectively.
a. Use a 99% confidence interval to estimate the mean of the population, µ.
b. How large a sample would be needed to estimate µ 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 σ2.