Examine Pollution Levels

Using the Cities.jmp sample data table, examine the distribution of different pollution measurements (ozone and lead) across selected cities in the United States.

First, examine ozone levels in the selected cities.

Select Help > Sample Data Library and open Cities.jmp.

Select Graph > Legacy > Treemap.

Select POP (population) and click Sizes.

Select city and click Categories.

Select X and Y and click Ordering.

Select OZONE and click Coloring.

Click OK.

The report window appears.

Figure 11.16 OZONE Levels for Selected Cities

From Figure 11.16, you observe the following:

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Los Angeles has a high level of ozone. It is also a western state, and that is reflected by its positioning in the treemap.

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Chicago and Houston have slightly elevated ozone levels.

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New York and Washington have slightly lower-than-average ozone levels.

Next, examine lead levels in the selected cities. Perform the same steps as before, but substitute OZONE with Lead for the Coloring variable.

Figure 11.17 Lead Levels for Selected Cities

From Figure 11.17, you observe the following:

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Cleveland and Seattle have high levels of lead. Cleveland is near the middle of the country, and Seattle is in the northwest. These locations are reflected by their positioning in the treemap.

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Interestingly, most other cities have rather low lead levels.

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Raleigh and Phoenix have missing values for lead measurements.