QUESTION 1 A researcher is interested in the effects of extra credit on motivation. He believes that students are motivated to do better on extra credit assignments than homework assignments. To test his hypothesis, the researcher selects two sections of the same college course. He then assigns the same assignments to both courses, although in one course the assignments are homework, and in the second the assignments are extra credit. O a. one sample z test O b. one sample t test O C. Independent samples t test O d. Dependent samples t test