Comparing Age-Sex Distribution in Mexico & the US: Population Pyramids - Prof. Eugene J. K, Assignments of Geodesy and Cartography

Download Comparing Age-Sex Distribution in Mexico & the US: Population Pyramids - Prof. Eugene J. K and more Assignments Geodesy and Cartography in PDF only on Docsity! GEOG 170 – Maps and Map Use Exercise 9 – Graph Construction: the Population Pyramid Discussion Date: November 14, 2003 Name _____________________________ Exercise Due Date: November 18, 2003 Discussion Section ___________________ Materials Needed: statistical tables for Mexico and the United States; the engineer’s scale; a set of colored pencils; a calculator; standard arithmetic graph paper (optional) Relevant Reading: Campbell, Chapter 15, “Maps and Graphs.” (especially pages 240-241) Nature of this Exercise You have now had experience in managing and mapping statistical data. In Exercise 9 you will have the opportunity to construct one kind of commonly used graph from statistical data, the population pyramid (profile). We will be using age and sex data for two countries, the United States and Mexico. The population pyramid is a graphic display of the age-sex distribution of a particular area. The area can be as large as a country or as small as a census tract. According to our textbook (p. 240), “The basic structure of a population profile consists of a horizontal baseline divided by a vertical centerline. Horizontal bars project from either side of the centerline, with the length of each bar representing the population in a specific age group. The bars on one side indicate the female segment of the population, and those on the other side represent males. The length of the bars may be based on either absolute numbers or on percentages, and the two types are interpreted differently.” Materials You may wish to bring some standard arithmetic graph paper with you. You can also scale standard notebook paper with the aid of your engineer’s scale. For the population pyramids statistical data accompanies this exercise on the age and sex composition of the populations of the United States and Mexico. You will be making separate pyramids for each country. 2 Procedure The work for this exercise will be on an individual basis. Do not share your graphs or interpretations. 1. Inspect the data – You are provided several columns of numbers about each country. Note, first, how the age data has been grouped. With the exception of the 80+ category, the age data is grouped into 5-year categories beginning at zero. You are particularly interested in the columns for population male, population female, percent male, and percent female. 2. What to graph – In making a population pyramid from these data you can use either absolute numbers or percentages. However, for this exercise we will be using the percentages. The reason for this is so that the pyramids for each country can have the same horizontal scale, i. e., the percentages. If absolute numbers were used each country would need a different absolute scale since their populations are very different. 3. Set up the graph – The information for females should go on the right side of your graph with males on the left. The vertical scale by 5 – year age groups should be in the middle. (For an example of this approach, see Figure 15.31, p. 241 in your text). The vertical scale will need to be tall enough to include all listed age groupings. (The two pyramids may be plotted on the same page or separately as you choose.) There will be two horizontal scales, one for each side of the pyramid, with zero points at the centerline. Values for males will increase to the left for males while female values increase to the right. Be sure your horizontal scale contains enough percentage values for your entire data set. Be sure to label each scale so that the numbers are easily understood. 4. Plotting the data – Begin with the bottom age category and scale the length of the bar according to the percentage of males on the left side and females on the right side. Simply proceed up the pyramid measuring the appropriate bar length for each age and sex category. 5. Color the bars – The final step involves coloring in the bars. Use different colors on the two graphs. 6. Repeat the process – Make a similar graph for the remaining country.