Scatter diagram

The scatter diagram is a simple graphical device to depict the relationship between two variables. A scatter diagram is composed of a horizontal axis containing the measured values of one variable and a vertical axis, representing the measurements of the variable. This diagram displays the paired data as a cloud of points. The density and direction of the cloud indicate how the tow variables influence each other. Although this diagram cannot prove that one variable causes the other, but they do indicate the existence of a relationship as well as the strength of that relationship.