A professor wanted to determine whether an online homework system improved scores on a final exam. In the fall semester, he taught a class using the online homework system (which meant students did their homework online and received instant feedback about their answers along with helpful guidance). In the spring semester, he taught a class without the homework system (which meant students were responsible for doing their homework the old-fashioned way dash– paper and pencil). The professor made sure to teach the two courses identically (same text, syllabus, tests, meeting time, meeting location, and so on). The table summarizes the results of the two classes on their final exam. Complete parts (a) through (e) .