The APA Publication Manual establishes technical guidelines for the layout of graphs. Generally, scatterplots, bar graphs, and line graphs should be constructed to be slightly wider than they are tall. The independent variable must be plotted on the $x$-axis, and the dependent variable on the $y$-axis. Furthermore, numerical values must increase from left to right on the $x$-axis and from bottom to top on the $y$-axis, with both axes strictly beginning at the value of zero.