The data in the accompanying table represents the percentage of workers who are members of a union for each U.S. state and the District of Columbia (AARP Bulletin, September 2009).
a. Construct a histogram of these data using class intervals of 0 to _5, 5 to _10, 10 to _15, 15 to _20, and 20 to _25.
b. Construct a dotplot of these data. Comment on the interesting features of the plot.
c. For this data set, which is a more informative graphical display—the dotplot from Part (b) or the histogram constructed in Part (a)? Explain.
d. Construct a histogram using about twice as many class intervals as the histogram in Part (a). Use 2.5 to _5 as the first class interval. Write a few sentences that explain why this histogram does a better job of displaying this data set than does the histogram in Part (a).