Six ninth-grade students and six 12th-grade students were asked: How many movies have you seen this month? Here are their responses. Ninth-grade students: 5,1, 2, 5, 3,8
12th-grade students: 4,2,0, 2, 3, 1

a. By hand, calculate the mean, variance, and standard deviation of each of these data sets. Which is more spread out, the ninth-grade or 12th-grade data set?
b. Make a graph of both data sets. Which of these data sets appears more spread out? Does your answer agree with your conclusion in part (a)?