60 CHAPTER 2 Exploring Data with Tables and Graphs Interpreting a Histogram. In Exercises 5–8, answer the questions by referring to the following Minitab-generated histogram, which depicts the weights (grams) of all quarters listed in Data Set 40 “Coin Weights” in Appendix B. (Grams are actually units of mass and the values shown on the horizontal scale are rounded.) 5. Sample Size What is the approximate number of quarters depicted in the three bars farthest to the left? 6. Class Width and Class Limits Give the approximate values of the class width, and the lower and upper class limits of the class depicted in the bar farthest to the left. 7. Relative Frequency Histogram How would the shape of the histogram change if the vertical scale uses relative frequencies expressed in percentages instead of the actual frequency counts as shown here? 8. Gap What is a reasonable explanation for the gap between the quarters with weights between 5.5 grams and 5.8 grams and the group of quarters with weights between 6.0 grams and 6.4 grams? (Hint: Refer to the columns of quarters in Data Set 40 “Coin Weights” in Appendix B.) Constructing Histograms. In Exercises 9–18, construct the histograms and answer the given questions. 9. Chicago Commute Time Use the frequency distribution from Exercise 13 in Section 2-1 on page 52 to construct a histogram. Does it appear to be the graph of data from a population with a normal distribution? 10. Presidents Use the frequency distribution from Exercise 14 in Section 2-1 on page 53 to construct a histogram. Does it appear to be the graph of data from a population with a normal distribution? 11. Old Faithful Use the frequency distribution from Exercise 15 in Section 2-1 on page 53 to construct a histogram. Does it appear to be the graph of data from a population with a normal distribution? 12. Tornadoes Use the frequency distribution from Exercise 16 in Section 2-1 on page 53 to construct a histogram. Does the histogram appear to be skewed? If so, identify the type of skewness. 13. Burger King Lunch Service Times Use the frequency distribution from Exercise 17 in Section 2-1 on page 53 to construct a histogram. Does the histogram appear to be normal?
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