A College Instructor Is Interested in Whether Assigning Mandatory Homework

A college instructor is interested in whether assigning mandatory homework affects students' grades.Since she is currently teaching two sections of the same class, the instructor assigns homework to one of the classes and just recommends homework problems to the second class.Then she determines the number of people in each class who will receive an A, B, C, D, or F on the final exam.What would be the appropriate statistical advice to give to the instructor?

A) It is unnecessary for her to analyze her data because you know from experience that mandatory homework improves your own grades in college classes.
B) Unfortunately, she will not be able to analyze the data because the dependent variable is not a scale variable.If, however, she were to use percentages or points on the final exam as the dependent variable, she would be able to analyze the data.
C) It is unnecessary for her to analyze the data because you know from experience that mandatory homework does not improve your own grades in college classes.
D) She would have more power to detect an effect of homework if she used the students' percentage grades (or point grades) and performed a parametric statistical test.