ASSIGNMENT: POPULATION PYRAMIDS
A diagram that shows the percentage of the total population of a state in five-year age categories is known as a population pyramid. On a pyramid, the percentage of Males is graphed on the left side of the vertical axis and that for Females is graphed on the right side of the axis. The shapes of population pyramids reveal three types of population growth. There is the 1. Rapidly growing population = broad base – e.g. developing countries, 2. Stable population = narrow base - rich developed countries, 3. Declining population = very thin base and large chest - highly affluent nations.
Go to the website -
http://www.census.gov/ftp/pub/ipc/www/idbsum.html. This is the US Census Bureau’s website containing summary
demographic data for several countries of the world. In the column reserved for
How to compute percentages for the “Cohorts or 5 year-age groups”
1. Collect data on a country’s population that is already classified into males/females and also into 5-year age categories e.g. 0-4, 5-9, 10-14 etc.
2. Take one category (i.e. males) then pick the cohorts in turn and compute the percentages that each 5-year age-group makes of the total population. For example, if the males aged between 0-4 were 32,000 of the population of a given state and the total population for the state (for the year) is 3,000,000 then the percentage for males aged 0-4 will be computed as: 32,000/3,000,000 x 100 = 1.06%
3. Repeat the process in 2 above and calculate the percentages for all 5-year age group categories for both males and females in turn.
4. Look for a graph sheet/paper then draw a central axis/line in the middle. Create a scale for the percentages of the population at the bottom of the axis (scale should not exceed 0-10%). After this, plot percentages of the population for 5-year age groups for males on the left hand side of the middle line on the graph and plot the percentages for females on the right hand side of the axis.
5. Use different shades or colors (of your choice) to show the portion of the graph for males and females.
Divide the pyramids into three sections by extending the lines marking the top boundaries of 10-15 year-olds and 60-65 year olds across the pyramid. This will create three sections:
a) 0 – 15 year olds = representing children, economically dependent group, b) 15 – 65 year olds, representing productive, working group who form the
labor force of a country and …
c) 65+ year olds representing senior citizens or retirees who are also
economically dependent on the country’s work force.
Hand in the graph sheet showing the two pyramids you have constructed, the paper on which you worked out the percentages of the total population for the various 5-year age groups, and your answers to the questions below:
1. Which of the two countries has a more rapidly growing population?
2. Which country has a declining population?
3. Which of the three broad age groups (0-14,
15-65 and 65+) in (a)
4. Give 2 reasons why there are fewer males than
females in the senior citizens’ age group (above 65 years) for
5. Why do you think the pyramid for
6. What account for a large concentration of
senior citizens in
7. Why is it important for a country to have more people within the 16-64 year group?
Identify the main population problem facing the (a)
9. Which country has a work force with a heavier tax burden and why is this so?
10. Calculate the dependency ratios for the 2 countries and comment on them.