A sample of 15 students was used to estimate the performance of graduates of a certain college on a standardized test taken by all the students of the college. It was found that the sample average...

A sample of 15 students was used to estimate the performance of graduates of a certain
college on a standardized test taken by all the students of the college.
It was found that the sample average score of these 15 students on the test was 85 with a
sample standard deviation of 15. What would be the 95% confidence interval for the average
score of the whole college population? If instead, it is known that this sample of 15 students
was taken only from a specific section of a class containing 30 students, what would be the
95% confidence interval for the average score of this class on this test?