Math, Statistics and Probability

To test the effectiveness of a business school preparation course, 8 students took a general business test before and after the course. The results are given below.

                                                         Exam Score                   Exam Score

                            Student                Before Course             After Course

                                 1                            530                                       670

                                 2                            690                                       770

                                 3                            910                                       1,000

                                 4                            700                                       710

                                 5                            450                                       550

                                 6                            820                                       870

                                 7                            820                                       770

                                 8                            630                                       610

Construct the 95% confidence interval for the mean difference between the exam scores before the course and exam scores after the course.