Your professor gives one of two types of exams, easy tests and hard tests. • 75% of the time he gives hard tests, 25% of the time he gives easy tests • Easy tests have an average score of 85 and a standard deviation of 5. • Hard tests have an average score of 70 and a standard deviation of 10. • Both types of tests produce normally distributed scores 1 (a) What is the probability of getting a score above a 90 on a test given by the professor? (b) What is the probability of getting a score below 80? (c) You have a friend of unknown ability. She reports that she got a score above 90 on the test. What is the probability it was an easy test? (d) What is the probability it was a hard test?