4 Line graphs

4.1 What is a line graph?

This section covers line graphs. We define the format, give some ideas about when it should be used, and draw some graphs. You can have a go at drawing a line graph in Activity 6, based on data that we supply.

A line graph, at its simplest, is a diagram that shows a line joining several points, or a line that shows the best possible relationship between the points. Sometimes the line will go through all of the points, and sometimes it will show the best possible fit. The line does not have to be a straight one; it can be a curve, though the techniques for drawing curved line graphs are beyond the scope of this course.