Ateacher returns an exam with possible scores ranging from 0 to 100 . the students suspect that the majority of them performed poorly on the exam and request summary statistics. the teacher provides the mean, which was 72 , as a summary statistic. a total of 400 students took the exam. some of the students find the mean to be high, based on talking to other students. they take a random sample of 15 students, and they find that the mean equals 71.5 while the median equals 62 . based on this result, we conclude that: