A **scatter plot** is the appropriate graph to show the relationship between two variables. In the case of a regression, the independent variable is on the horizontal axis, and the dependent variable is on the vertical axis.

*Example of a scatter plot, in this case indicating the relationship between species richness and wildlife reseve area. The right hand panel shows the same plot with the linear model overlaid*

Since linear regression is a parametric test, you may need plot histograms of each variable to check whether they are normally distributed.

*Example histogram, in this case showing the distribution of sperm length. The data are approximately normally distributed*