Diagram in which a line, formed by line segments, connects the points that represent the data.
A broken line graph is a diagram that has a horizontal axis divided into units of time and a vertical axis that displays the values of the qualitative characteristic studied, and in which the data recorded are represented by points that are then connected to one another by segments to form a broken line that illustrates the evolution of the phenomenon under consideration.
Some authors call the broken line graph a line graph.
The broken line graph can be likened to a rod graph in the sense that the segments connect the vertices of the rods.
The broken line graph is particularly useful for representing the distribution of a quantitative statistical characteristic. We often use it to illustrate a phenomenon that evolves over time.
Example
Here are the data observed for temperatures from July 22nd to July 31st, inclusive: The illustration on the right reproduces this data in the form of a broken line graph. |
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We can make several interpretations based on this graph.
- Between July 22nd and 25th, the temperature increased by 8 degrees.
- Between July 27th and 29th, the temperature dropped 9 degrees.
- On July 26th, it was hotter than on July 22nd
- Etc.