Here are some scores from a group of 10 test-takers: 15, 12, 12, 16, 15, 12, 15, 17, 10, 15. Here are those same scores added together: 15+12+12+16+15+12+15+17+10+15 = 139. That total (139) divided by the 10 scores that produced it yields 139 / 10 = 13.9. Huzzah! We’ve just found the: