A Scatterplot is used to display the relationship between two quantitative variables plotted along two axes. A series of dots represent the position of observations from the data set. The independent variable is generally plotted along the horizontal (X) axis and the dependent (or responsive) variable along the vertical (Y) axis. If no dependent variable exists, either type of variable can be plotted on either axis; in this case, the scatter plot will illustrate only the degree of correlation (and not causation) between two variables.