The salaries (in millions of dollars) for 31 NFL teams for a specific season are given in this frequency distribution.
Class limits Frequency
39.9–42.8 ........2
42.9–45.8 ........2
45.9–48.8 ........5
48.9–51.8 ........5
51.9–54.8 ........12
54.9–57.8 .......5
Construct a histogram, a frequency polygon, and an give for the data; and comment on the shape of the distribution.