For example, we will show using JMP-IN how the distribution of calories in a cup of breakfast cereal compare among different fibre groups. Typically, separate graphs are constructed for each group. However, the key point is that the graphs should have the same scale and axes, be the same size to make the comparison as simple as possible, and aligned either vertically or horizontally to make easy comparisons. It is difficult to compare concentrations except by density. You saw and example earlier with the Darwin data.
Groups are difficult to compare since length of leaves depends upon sample size.
Be sure the axis are the same, class widths are the same, vertical scale is the same, and that the data is measured in percentages.