a. If appropriate, construct a 95% confidence interval estimate for the average exam mark of students who had a mark of 65% on the second test of a statistics course (using the data set described in Exercise 11).
b. If appropriate, construct a 95% interval estimate for the exam mark of a student who received 65% on the second test of a statistics course (using the data set described in Exercise 11). How does this compare with the estimate for the average exam mark of students who had a mark of 65% on the second test (your answer to Exercise 14a)? Why is there a difference?