The director of admissions at a large university advises parentsof incoming students about the cost of textbooks during a typicalsemester. He selected a sample of 100 students and recorded theirtextbook expenses for the semester. He then calculated a samplemean of $675.60 and a sample standard deviation of $45.20. You mayassume that the distribution of textbook expenses is approximatelynormally distributed.
(a) Is there sufficient evidence that the population meantextbook expense per semester is above $665? You should justifyyour answer with a hypothesis test at the 5% significancelevel.
(b) Construct a 95% confidence interval estimate of thepopulation mean textbook expense per semester.
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