2.43 [EX02-043] The speeds of 55 cars were measured by a radar device on a city street:

27 23 22 38 43 24 35 26 28 18 20 25 23 22 52 31 30 41 45 29 27 43 29 28 27 25 29 28 24 37 28 29 18 26 33 25 27 25 34 32 36 22 32 33 21 23 24 18 48 23 16 38 26 21 23

a. Classify these data into a grouped frequency distribution by using class boundaries 12–18, 18–24, . . . , 48–54.

b. Find the class width.

c. For the class 24–30, find the class midpoint, the lower class boundary, and the upper class boundary.

d. Construct a frequency histogram of these data.

FYI Use the computer or calculator commands on pages 61–63 to construct a histogram for a given set of data.