Theory question 302
Statistical Maps and DiagramsUse the data in the table below to answer the questions that follow: Country B's population figures (in millions) by State in the year 2005.
State A: 40
State B: 35
State C: 25
State D: 50
TOTAL: 150
(a) Construct a pie chart to represent the data. (b) Highlight any two problems in the use of pie charts. (c) State one other method that could be used to represent the above information.
Show the model answer
(a) Angles = value ÷ 150 × 360°: A = 96°; B = 84°; C = 60°; D = 120° (total 360°). Draw a circle, measure each sector with a protractor from a vertical radius, shade or label each sector with state and value, add a key and title.
(b) Angles must be calculated, which takes time; small values give very thin sectors that are hard to draw and read; hard to compare sectors of similar size; actual values are not shown unless written; unsuitable for many components; absolute changes over time are hard to show.
(c) Simple bar graph; divided (component) bar graph; dot map or proportional symbols.
Show the angle calculation for each state.