### 9.2 Describing "Average"

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• Math Help

In Example 2, note that in each graph the vertical scale represents age groups. So, 0 represents the 0 to 4 age group, 5 represents the 5 to 9 age group, 10 represents the 10 to 14 age group, and so on.

In the solution to Example 2, young age group refers to ages 0 to 14, working age group refers to ages 15 to 59, and old age group refers to ages 60 and over.

• Consumer Suggestion

Check out this website to see an age distribution chart on Facebook users in America. The chart is from 2008, so the numbers have grown significantly. Do you think the distribution has changed or stayed relatively the same?

• Checkpoint Solution
1. This is the population pyramid of Mexico. Mexico is a newly industrialized country, which is the transition stage between a developing country and a developed country. Mexico's population pyramid is beginning to change from an expansive pyramid to a constrictive pyramid. The life expectancy in a newly industrialized country like Mexico is higher than the life expectancy in a developing country like Afghanistan, so the pyramid is not as bottom-heavy as Afghanistan's.
2. This is the population pyramid of Canada. Canada is a developed country and has a population pyramid similar to the population pyramid of the United States. Canada has a higher life expectancy than Mexico and Afghanistan, so a larger percent of its population is in the older age groups.
3. This is the population pyramid of Afghanistan. Afghanistan is a developing country with a lower life expectancy than countries like the United States and Canada and newly industrialized countries like Mexico. Because Afghanistan is a very poor developing country, it has a high birth rate and a high death rate. This results in Afghanistan's population pyramid being the most bottom-heavy of the three shown. Afghanistan's population pyramid is a classic example of an expansive population pyramid.

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