A population pyramid (age structure diagram) or "age-sex pyramid" is a graphical illustration of the distribution of a population (typically that of a country or region of the world) by age groups and sex; it typically takes the shape of a pyramid when the population is growing.
A population pyramid is a way to visualize two variables: age and sex. They are used by demographers, who study populations. A population pyramid is a graph that shows the distribution of ages across a population divided down the center between male and female members of the population.
Interpreting population pyramids
The shape of the population pyramid efficiently communicates considerable information about the age-sex structure of a specific population.
A broad-based pyramid indicates that people in the younger age categories make up a relatively large proportion of the population, and a narrow or pointed top indicates that older people make up a relatively small proportion of the population.
In the older age groups of many populations, the number of females is much greater than the number of males; this is reflected in the shape of the pyramid, such that the bars on the right side of the central axis (the female side) are longer than those on the left (male) side.
The median age of the population would be the age group (bar) represented by the point on the vertical axis that equally divides the area within the pyramid (equal areas within the pyramid fall above and below the age represented by the bar).
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Organization of data
In a population pyramid, the size of the population under investigation is depicted on the horizontal axis, and age is aligned on the vertical axis.
The result is a series of bars stacked on top of one another, each representing an age category (typically in 5-year age groups), with the youngest age group represented by the bottom bar and the oldest age group by the uppermost bar.
The horizontal length of each bar represents the number of individuals in the specific age group for the population depicted.
The age groups that correspond to each bar are displayed along the central axis or along one side or both sides of the graph.
Often the years of birth for each age category are also displayed on the graph.
To maintain proportionality, the age groups are the same size (e.g., 1-year, 5-year, or 10-year age groups), and the bars are all of equal height.
The age (vertical) axis is often truncated at the age group 80 to 84, depending on the data available for the population depicted.
For some populations, data for the older age groups are incomplete or inaccurate or there are few people in the older age categories.
Population pyramids intended for comparison should be drawn to the same scale and should depict the same age categories.
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Overview
population pyramid, graphical representation of the age and sex composition of a specific population.
The age and sex structure of the population determines the ultimate shape of a population pyramid, such that the representation may take the form of a pyramid, have a columnar shape (with vertical sides rather than sloped sides), or have an irregul.
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What are population pyramids used to show?
What do population pyramids show.
A population pyramid, using a paired bar chart-type graphic, shows the numbers or percentages of males and females in each age group.
This type of graphic provides a very clear picture of a population’s age-sex composition.
It can also be used for displaying future trends in a population.
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What are the three population pyramids?
There are three types of population pyramids:
- expansive
- constrictive
- stationary
Expansive
population pyramids depict populations that have a larger percentage of people in younger age..
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What does population pyramid stand for?
What does population pyramid stand for.
What does POPULATION PYRAMID mean.
A population pyramid, also called an age pyramid or age picture diagram, is a graphical illustration that shows the distribution of various age groups in a population, which forms the shape of a pyramid when the population is growing.
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What part of the population pyramid shows the life expectancy?
A wide middle, tall pyramid means an ageing population, suggesting that there is a long life expectancy.
Some reasons for high birth rates include:
- need for large families
- eg to work in rural
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