6.10 A set of final examination grades in an introductory statistics course is normally distributed, with a mean of 73 and a standard deviation of 8. a. What is the probability of getting a grade below 91 on this exam? b. What is the probability that a student scored between 65 and 89? c. The probability is 5% that a student taking the test scores a higher than what grade? d. If the professor grades on a curve (i.e., gives A's to the top 10% of the class, regardless of the score), are you better off with a grade of 81 on this exam or a grade of 68 on a different exam, where the mean is 62 and the standard deviation is 3? Show your answer statistically and explain