Which of the following scenarios should be analyzed as paired data?
a) Students take a MCAT prep course. Their before and after scores are compared
b) 20 male and 20 female’s students in class take a midterm. We compare their scores.
c) A group of college freshmen are asked about the quality of the university cafeteria. A year later, the same students are asked about the cafeteria again. Do student's opinions change during their time at school?