Line graphs
There are a variety of ways line graphs can be used to clearly display complex information.
Each axis is named by the quantity labelled on it. This might be \(x\) and \(y\), or time and temperature.
If one quantity depends on another, the dependent quantity is always marked on the vertical axis.
Example
A courier firm charges the following amounts for delivery of parcels.
The cost depends on the amount of parcels, not the amount of parcels on the cost.
Question
A company's sales of a product over the first half of the year are shown in this table.
| Month | Sales |
| January | \(£3\,500\) |
| February | \(£1\,300\) |
| March | \(£4\,200\) |
| April | \(£6\,000\) |
| May | \(£4\,000\) |
| June | \(£3\,500\) |
| Month | January |
|---|---|
| Sales | \(£3\,500\) |
| Month | February |
|---|---|
| Sales | \(£1\,300\) |
| Month | March |
|---|---|
| Sales | \(£4\,200\) |
| Month | April |
|---|---|
| Sales | \(£6\,000\) |
| Month | May |
|---|---|
| Sales | \(£4\,000\) |
| Month | June |
|---|---|
| Sales | \(£3\,500\) |
How would you show this information in a line graph?
Choose a scale for the vertical axis and mark the months at equal intervals along the horizontal axis.
Record the data on the graph and join up the points.
