Measures of the Location of the Data · Exercise 19

Six hundred adult Americans were asked by telephone poll, "What do you think constitutes a middle-class income?" The results are in. Also, include the left endpoint but not the right endpoint.

\begin{array}{|c|c|}\hline \text{Salary ($)} & \text{Relative Frequency} \\ \hline \text{< 20,000} & \text{.02} \\ \hline \text{20,000–25,000} & \text{.09} \\ \hline \text{25,000–30,000} & \text{.19} \\ \hline \text{30,000–40,000} & \text{.26} \\ \hline \text{40,000–50,000} & \text{.18} \\ \hline \text{50,000–75,000} & \text{.17} \\ \hline \text{75,000–99,999} & \text{.02} \\ \hline \text{100,000+} & \text{.01} \\ \hline\end{array}

(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.
(a) Should all bars have the same width, based on the data? Why or why not?
(b) How should the < 20,000 and the 100,000+ intervals be handled? Why?
(d) Find the 40^th and 80^th percentiles.
(e) Construct a bar graph of the data.

OpenStax, Statistics · §2.3 Measures of the Location of the Data · Exercise 19