The head librarian at the National Library of Australia has asked her assistant for an interval estimate of the mean number of books checked out each day. The assistant provided the following 95% interval estimate: from a to b books per day. The interval was constructed by using a sample of 81 days of data with a sample mean of 325 books and a sample standard deviation of 150 books checked out per day. What is the value of b? Select one: O a. None of the answers listed. b. 361.17 O c. 357.67 O d. 291.83 O e. 296.33