A statistics instructor at a large western university would like to examine the relationship (if any) between the number of optional homework problems students do during the semester and their final course grade. She randomly selects 12 students for study and asks them to keep track of the number of these problems completed during the course of the semester. At the end of the class each student's total is recorded along with their final grade. The data follow in Table 1.

Ex . Ey nin -\fTable 1: Course grade versus the number of optional homework problems completed. Problems CourseGrade Prb* Grd 51 62 3162 58 68 3944 62 66 4092 65 66 4290 68 67 4556 76 72 5472 77 73 5621 78 72 5616 78 78 6084 84 73 6132 85 76 6460 91 75 6825 873 848 62254 EPrb EGrd EPrb *Grd\fcalc\f