Problem 6 In a Mathematics class, there were only 18 students taking the class. On the first test of the semester, these students had the following test scores. We can consider this class as our population of study. 80, 81,76, 68, 85, 91, 73, 78,87, 75, 79,99, 79, 82, 82, 60, 99, 57 a) Find the mean and the standard deviation. Use the proper notation for the mean and standard deviation. b) Are there any statistically significant (unusual) test scores in the above data set? (Using the z-score of the data value, you can determine if the value is unusual when the z-score is less than -2 and more than 2). Explain your