Chapter 2: Graphs, Charts, and Tables--Describing Your Data
Chapter 2: Graphs, Charts, and Tables--Describing Your Data
Chapter 2: Graphs, Charts, and Tables--Describing Your Data
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58 CHAPTER 2 • GRAPHS, CHARTS, AND TABLES—DESCRIBING YOUR DATA<br />
TABLE 2.8 March 2005 New Car Sales for the<br />
Top Six Automobile Companies<br />
(United States)<br />
Car Company<br />
March 2005 Sales<br />
General Motors 426,114<br />
Ford 305,173<br />
DaimlerChrysler 243,165<br />
Toyota 203,443<br />
Honda 128,548<br />
Nissan 106,042<br />
Source: www.theautochannel.com/news/2005/04/<br />
22/046636.html<br />
CHAPTER OUTCOME #4<br />
by the six largest automobile companies in the world. Although the table format is informative,<br />
a graphical presentation is often desirable. Because the car sales data are summarized<br />
by car company, a bar chart would work well in this instance. The bars on a bar chart<br />
can be vertical (called a column bar chart) or horizontal (called a horizontal bar chart.)<br />
Figure 2.10 illustrates an example of a column bar chart. The height of the bars corresponds<br />
to the number of cars sold by each company. This gives you an idea of the sales<br />
advantage held by General Motors in March 2005.<br />
One strength of the bar chart is its capability of displaying multiple variables on the<br />
same chart. For instance, a bar chart can conveniently compare new car sales data for<br />
March 2005 <strong>and</strong> sales for the same month the previous year. Figure 2.11 is a horizontal bar<br />
chart that does just that. Notice that both GM <strong>and</strong> Ford had a decline in car sales in March<br />
between 2004 <strong>and</strong> 2005.<br />
People sometimes confuse histograms <strong>and</strong> bar charts. Although there are some similarities,<br />
they are two very different graphical tools. Histograms are used to represent a<br />
frequency distribution associated with a quantitative (ratio or interval-level) variable. Refer<br />
to the histogram illustrations in Section 2-1. In every case, the variable on the horizontal<br />
axis was numerical, with values moving from low to high. There are no gaps between the<br />
histogram bars. On the other h<strong>and</strong>, bar charts are used when the variable of interest is<br />
categorical, as in this case in which the category is car company.<br />
FIGURE 2.10<br />
Bar Chart Showing<br />
March 2005 New Car<br />
Sales<br />
450,000<br />
400,000<br />
350,000<br />
300,000<br />
Car Sales<br />
250,000<br />
200,000<br />
150,000<br />
100,000<br />
50,000<br />
0<br />
General<br />
Motors<br />
Ford<br />
Daimler<br />
Chrysler<br />
Toyota<br />
Honda<br />
Nissan<br />
Automobile Company
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