Question: Refer to the data in the table that lists SAT scores before and after the sample of 10 students took a preparatory course (based on data from the College Board and “An Analysis of the Impact of Commercial Test Preparation Courses on SAT Scores,” by Sesnowitz, Bernhardt, and Knain, American Educational Research Journal, Vol. 19, No. 3.)

a. Is there sufficient evidence to conclude that the preparatory course is effective in raising scores? Use a 0.05 significance level.

b. Construct a 95% confidence interval estimate for the mean difference between the before and after scores. Write a statement that interprets the resulting confidence interval.