A professor of statistics noticed that the marks in his course are normally distributed. He also noticed that his morning classes average 73% with a standard deviation of 9% on their final exams. His afternoon classes average 79% with a standard deviation of 12%.

A. What is the probability that a randomly selected student in the morning class has a higher final exam mark than a randomly selected student from an afternoon class?

Probability =

B. What is the probability that the mean mark of four randomly selected students from a morning class is greater than the average mark of four randomly selected students from an afternoon class?

Probability =

You can earn partial credit on this problem.