8. The grades on an Anthropology exam had a mean of 77.3 points and a standard deviation of 7.1 points. The instructor did not construct a graph for the scores on the exam, and so they do not know the shape of the distribution. a) Determine the minimum percentage of students that scored within 1.5 standard deviations of the mean. b) Determine the minimum percentage of students that scored between 63.1 and 91.5 points