9. Last year, Satsville High School ran nine classes of mathematics of data management, each with the same number of students. The class-average scores at year-end were as follows: 80.4 70.5 68.9 72.7 83.1 78.6 76.6 74.4 75.8 a) Find the mean and standard deviation of these class-average scores. b) How is the standard deviation of the class-average scores related to the underlying distribution of individual scores? c) A study of the scores for all of the data-management students found that the scores were approximately normally distributed, with a mean of 75.7 and a standard deviation of 24.3. Given that all nine classes were the same size, find the most likely value for this class size. Explain your