[EX02-141] On the first day of class last semester, 50 students were asked for the one-way distance from home to college (to the nearest mile). The resulting data follow:

6 5 3 24 15 15 6 2 1 3 5 10 9 21 8 10 9 14 16 16 10 21 20 15 9 4 12 27 10 10 3 9 17 6 11 10 12 5 7 11 5 8 22 20 13 1 8 13 4 18

a. Construct a grouped frequency distribution of the data by using 1–4 as the first class.

b. Calculate the mean and the standard deviation.

c. Determine the values of ¯ x  2s, and determine the percentage of data within 2 standard deviations of the mean.