Suppose that a school is studying the average number of hours students study for classes per week. According to research from 2010 the school spent an average of 18 hours a week studying for classes with a standard deviation of 6.4 hours. The school wants to study if this average has changed. To do this they take a random sample of 81 current students and find that the average student spent 16.2 hours studying.

B. Construct a 95% confidence interval for the average number of hours studied by the students per week. Make sure to interpret your interval