5 Line graphs

Line graphs are a very useful way to spot patterns or trends over time. The example below shows the population over a number of years of a rare type of bird on a small island. Just from looking at the graph we can see that the population of birds is going down over time, with a brief period between 2006 and 2007 where there was a slight rise.

If you were looking at how to increase the numbers of these birds, you would look more closely at what happened over those years and see what circumstances might have helped the population grow. Once you had discovered this, you could try to replicate it over coming years to try and increase the population.

Figure _unit4.5.1  Figure 15 A graph to show the population of the Kakapo bird on Stewart Island

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A line graph. The horizontal axis is labelled ‘Year’ and has 10 data points from 2001 to 2010. The vertical axis is labelled ‘Population’ and has 7 data points from 0 to 60. The line shows an overall downward trend from left to right, with a slight upwards rise around 2006–2007.

 Figure 15 A graph to show the population of the Kakapo bird on Stewart Island

Now that you understand how useful line graphs can be and how they can be used, next you’ll learn how to draw and interpret them.