Chapter 9, Problem 88CRE

Exam Grades The final exam grades for a sample of day-time statistics students and evening statistics students at one college are reported. The classes had the same instructor, covered the same material, and had similar exams. Using graphical and numerical summaries, write a brief description about how grades differ for these two groups. Then carry out a hypothesis test to determine whether the mean grades are significantly different for evening and daytime students. Assume that conditions for a $t\text{-test}$ hold. Select your significance level.

Daytime grades: $100,100,93,76,86,72.5,82,63,59.5,53,79.5,67,48,42.5,39$

Evening grades: $100,98,95,91.5,104.5,94,86,84.5,73,92.5,86.5,73.5,87,72.5,82,$ $68.5,64.5,90.75,66.5$