Explanation?

Hypothesis Test with an Unknown Population Standard Deviation Suppose a librarian states that the average amount of time that a library book is checked out is 12 days. A random sampling of 15 library books reveals a sample mean of 13 days and a sample standard deviation of 1 day. Is there convincing evidence that the librarian is incorrect? (Assume a 5% significance level.) Ho:/ = 12 Hail # 12 Useful tools: Normal Distribution Calculator t-Distribution Calculator a. Conduct a hypothesis test and report the p- value. P = (Include four decimal places) b. At the 5% significance level, we conclude that there is sufficient evidence to refute the librarian's claims. o True o False