Acollege instructor is interested in whether assigning mandatory homework affects students' grades. she is currently teaching two sections of the same class. therefore, 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 that will receive either an a, b, c, d, or f on the final exam. what type of statistical test would the instructor use to analyze her data?
a) chi-square test for goodness-of-fit
b) chi-square test for independence
c) analysis of variance
d) independent-samples t test