Here are the total scores of a sample of students in an introductory statistics course: 64- 93 54- 76 73 90 64- 55 88 71 Previous experience with this course suggests that these scores should come from a distribution that is Normal with mean 73 and standard deviation 12. a. If the grading policy is to give a grade of A to the top 24% of the scores based on the Normal distribution with mean 73 and standard deviation 12, what is the cutoff for an A? b. What percentage of the 10 students above received an A based on part a? c. If the grading policy is to give a grade of F to the bottom 4% of the scores based on the Normal distribution with mean 73 and standard deviation 12, what is the cutoff for a passing grade? d. What percentage of the 10 students failed the course based on part c