While writing an article on the high cost of college education, a reporter took a random sample of the cost of new textbooks for a semester. The random variable x is the cost of one book. Her sample data can be summarized by the following. (Give your answers correct to two decimal places.) n = 30, Σx = 3594.6, and Σ(x - x)2 = 9778.4
(a) Find the sample mean, x.
(b) Find the sample standard deviation, s.
(c) Find the 99% confidence interval to estimate the true mean textbook cost for the semester based on this sample.
Lower Limit
Upper Limit