A statistics professor formed the opinion that students who handed in quiz and exams early out-performed students who handed in their papers later. To develop data to decide whether her opinion is valid, she recorded the amount of time (in minutes) taken by students to submit their midterm tests (time limit 90 minutes) and the subsequent mark for a sample of 12 students. Time 90 73 86 85 80 87 90 78 84 71 72 88
Mark 68 65 58 94 76 91 62 81 75 83 85 74