Statistics is a course with a bad reputation. Students tend to expect that they will have difficulty with the course, even when they do not know exactly what the course is about. A student decides that he wants to place statistics in a proper context, and he collects data on a random sample of students studying in their third semester (the beginning of second year). The student attempts to predict the statistics mark from the marks in other courses. Help him by deciding which of the possible models is best.