The head librarian at the Library of Congress has asked her assistant for an interval estimate of the mean number of books checked out each day. The assistant provides the following interval estimate: from 740 to 920 books per day. If the head librarian knows that the population standard deviation is 150 books checked out per day, and she asked her assistant for a 95% confidence interval, approximately how large a sample did her assistant use to determine the interval estimate?
The question only tells us that the assistant provides the following interval estimate: from 740 to 920 books ...
This solution provides a detailed explanation of how to determine the interval estimate for a 95% confidence interval.