8.30 A tuition center employs two statistics professors. The head of the tuition center wants to know if there is a significant difference in the average final exam scores between the students taught by the two professors.

Answer this question with a 90% confidence interval using the following data from random samples of students taught by the two different teachers. Discuss the assumptions.

Professor I Professor II Mean 81 75 Standard deviation 9 3 Sample size 10 15