A professor believes that the midterm score in her class is a good prediction of the final exam score. If the mean for the midterm ( M _x) was 77, with s _x = 18.5, and the mean for the final exam ( M _y) was 84, with s _y = 14, what final exam score would be predicted for someone whose midterm was 77?

a. 77 b. 84 c. 91. d. Cannot be answered without knowing Pearsons r