Line graphs can easliy and clearly present a large quantity of statistical data. Economists use line graphs to illustrate patterns or trends over time and to explain the relationship between two or more variables. A varible is a factor with a value that can be change. There are 3 steps that can help you use a graph and understand the data.

1. Identify the type of information presented on the graph: Before you can begin to interpret the information on a graph, you must identify specifically what is being shown. The title of the graph and the axes' labels indicate the meanings of the points and lines on the graph.
2. Read the data shown on the graph and study the graph's axes carefully: Before you start to study the overall patterns, carefully look at the specific points on the graph.
3. Study the data on the graph to look for relationships or draw conclusions about a topic: Use the graph to draw conclusions about the relationship for example, time spent on practing for basketball and the number of points scored per game.