Six hundred adult Americans were asked by telephone poll, "What do you think constitutes a middle-class income?"

The results are in Table 2.71. Also, include left endpoint, but not the right endpoint.

a. What percentage of the survey answered "not sure"?

b. What percentage think that middle-class is from $25,000 to $50,000?

c. Construct a histogram of the data.
i. Should all bars have the same width, based on the data? Why or why not?
ii. How should the

d. Find the 40^th and 80^th percentiles

e. Construct a bar graph of the data

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Salary ($) Relative Frequency < 20,000 0.02 20,000-25,000 0.09 25,000-30,000 0.19 30,000-40,000 0.26 40,000-50,000 0.18 50,000-75,000 0.17 75,000-99,999 0.02 100,000+ 0.01 Table 2.71