1. Unit 5D
Graphics in the Media
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2. Graphics Beyond the Basics
A multiple bar graph has two or more sets of bars that allow comparison between two or more data sets. All the data sets must involve the same categories so that they can be displayed on the same graph.
A stack plot shows different data sets in a vertical stack. Stack plots usually use either stacked bars or stacked line graphs.
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3. A Multiple Bar Graph
The following multiple bar graph shows how education affects personal employment.
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4. A Stack Plot
The following stack plot shows trends in death rates from four diseases.
Illustrate with this graphic how color can help the researcher identify, at a glance, patterns and key geographical regions that may be of an influence in the context of the study.
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5. Reading a Stack Plot What was the death rate for tuberculosis in 1930?
About 220 – 100 = 120 deaths per 100,000
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6. A Few Cautions about Graphics
Perceptual distortions: Many graphics are drawn in a way that distorts our perception of them.
Watch the scales: It can be visually deceptive if you do not study the scales carefully.
Percentage change graphs: Graphs that show percentage change can be misleading unless you interpret them with great care.
Pictographs: Pictographs are graphs embellished with additional artwork. The artwork may make the graph more appealing, but can also mislead.
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7. Perceptual Distortion
The lengths of the dollars to the right represent the data, but your eyes tend to focus on the area.
Show students why many two-dimensional graphics can distort our perspective either intentionally or unintentionally. Explain the idea of area versus length of the dollars.
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8. Different Vertical Scales
Illustrate and stress the importance of choosing a scale when graphing data and reading a graph's scale carefully. Help students realize that the choice of a scale can change the look of the data.
Both graphs show the same data, but they look very different because their vertical scales have different ranges.
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9. Different Horizontal Scales
Illustrate and stress the importance of choosing a scale when graphing data and reading a graph's scale carefully. Help students realize that the choice of a scale can change the look of the data.
It appears that the world population has been rising linearly. However, the time intervals on the horizontal axis are not uniform in size.
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