Illuminations: State Data Map

# State Data Map

Information can be represented in many ways, and this applet allows the user to represent data about the states using colors. The state with the highest data value is darkest; other states are shaded proportionally. Investigate any of the data provided—or enter data of your own!

### Instructions

 Each state in the map below is shaded a percentage of color proportional to the largest data for any state. Using the Population data set, for example, California (population 33,871,648) is shaded at 100%, because it has the greatest population; but Colorado (population 4,301,261) is only shaded at 13%, because 4,301,261 ÷ 33,871,648 ≈ 0.13. Choose a Data Set to view various state data. Alternatively, enter values for each state in the table; then, click Update Map to view the results. The Clear Data button can be used to replace all state data with X's. An X indicates that there is no data entered for that state, and data for that state will not influence the mean or five-number summary. (By contrast, a data value of "0" will influence the measures of center.) Click Hide Map Numbers to remove the data from the map. (The data will still be displayed in the table, however.) Change the color of the shading by selecting a different color from the Map Color pull‑down menu.

### Exploration

 Select the Data Set for Land Area. As expected, the states that look bigger are a darker color, because larger states have more area. (Alaska is not drawn to scale, so even though it does not appear to be the largest state, it is the darkest. Indeed, it has almost three times the area of the second largest state, Texas.) An attribute that is not obvious by visual inspection is the state population. Choose Population from the Data Sets menu. Do the largest states have the largest populations? Now, combine these two elements by opening the Data Set for Population Density. You'll notice that most of the states appear in a very light shade. Why does that happen? Something within the data causes this to occur—what is it? Identify the element that causes problems, then replace the data with an X and click Update Map. How does the map change?

### NCTM Resources

 Principles and Standards for School Mathematics (Book and E-Standards CD)

### Lessons

 More and Better Mathematics for All Students
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