2.4 Displaying data on a graph or chart

You have seen that, provided you have both an x- and a y-coordinate, you can plot a point on a chart. So if a set of data consists of pairs of data values, then that data can be plotted on a graph. This enables patterns between the data to be assessed visually, as well as mathematically. This is for future study though!

There are several steps to take when drawing a graph, which can be summarised as follows:

• Choose an appropriate scale for both axes.
• Label both axes, including a brief description of the data and the units.
• Give your graph a suitable title.
• State the source of data.
• Plot the points accurately.
• Join the plotted points with a line or smooth curve if appropriate.

Following these steps will ensure that any graph is clear, easy to read and well presented.

Let’s look at one of these steps in more detail now – choosing the scales.