A lecturer at UCI wants to assess if people perceive their lectures differently when they are given in person versus when they are given as pre-recorded videos. They are teaching a class with 80 students. Half of them, randomly selected, are given in person lectures for a given quarter, while the other half are to watch pre-recorded lectures. The students are then asked to score the lectures at the end of the quarter. All following numbers were computed from the sample: The average score for the in-person lectures was 73 (SD 5) while the average score for the pre-recorded lectures was 77 (SD 9.1).

Required:
Construct a 95% confidence interval for the difference in the average score of the in person lectures and the average score of the pre-recorded lectures.