### 9.3 Describing Dispersion

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• Math Help

A moving average is another way to analyze a set of data. Depending on the length of time, it can show short-term or long-term changes. For a 101-day moving average, as shown in the Checkpoint, the first point plotted is the average temperature of the first 101 days of 1955 (from January 1 to April 11). For the second 101 days, you subtract the first day and add another day to the end. So, the second plotted point is the average temperature from January 2 to April 12. Following this pattern, the third plotted point is the average temperature from January 3 to April 13, and so on.

• Consumer Suggestion

Global warming has been debated for years, but it is undeniable that Earth's climate is changing. Scientists have studied data and concluded that average temperatures have risen 1.5 degrees Fahrenheit and sea levels have risen 8 inches over the last century. These changes may seem mild, but for the animals and vegetation inhabiting Earth, they seem much more extreme. To learn more about global warming, causes and effects, and how you can get involved, visit The Discovery Channel or the National Wildlife Federation.

• Checkpoint Solution

The line graph would be more helpful than the histogram because the line graph shows how the temperature has changed over time and the histogram does not.

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``` __   __     ___     _    _      ___     __   __
\ \\/ //   / _ \\  | || | ||   / _ \\   \ \\/ //
\   //   | / \ || | || | ||  | / \ ||   \   //
/ . \\   | \_/ || | \\_/ ||  | \_/ ||   / . \\
/_//\_\\   \___//   \____//    \___//   /_//\_\\
`-`  --`   `---`     `---`     `---`    `-`  --`

```