8.12 Tough course? A friend tells you, “In the 7:30 A.M. lecture for Statistics 101, 9 students failed, but 20 students failed in the 1:30 P.M. lecture. The 1:30 P.M. prof is a tougher grader than the 7:30 A.M. prof.” Explain why the conclusion may not be true. What additional information would you need to compare the classes?