Time series
The table shows the number of visitors per quarter (every three months) to a seaside town.
| Quarter (year) | 1 (2005) | 2 (2005) | 3 (2005) | 4 (2005) | 1 (2006) | 2 (2006) | 3 (2006) | 4 (2006) |
| Visitors (thousands) | 14 | 24 | 9 | 8 | 12 | 22 | 11 | 7 |
| Quarter (year) |
|---|
| 1 (2005) |
| 2 (2005) |
| 3 (2005) |
| 4 (2005) |
| 1 (2006) |
| 2 (2006) |
| 3 (2006) |
| 4 (2006) |
| Visitors (thousands) |
|---|
| 14 |
| 24 |
| 9 |
| 8 |
| 12 |
| 22 |
| 11 |
| 7 |
The Values, typically letters or numbers. can be plotted to give a time series graph, which shows the frequencies over time.
Notice that plotting the points is similar to that for scatter diagrams. We are most likely to be interested in how time affects the number of visitors, so time (the top row of the table) goes on the horizontal axis.
The points are then joined with straight lines (not curves).
From the graph, it can be seen that there is a large fluctuation in the number of visitors during each year. However, there is a pattern that repeats each year. For example, many more people visit in the 2nd quarter than visit in the 4th quarter.