Bar Diagram Math

"Bar graphs can ... be used for more complex comparisons of data with grouped bar charts and stacked bar charts. In a grouped bar chart, for each categorical group there are two or more bars. These bars are color-coded to represent a particular grouping. For example, a business owner with two stores might make a grouped bar chart with different colored bars to represent each store: the horizontal axis would show the months of the year and the vertical axis would show the revenue. Alternatively, a stacked bar chart could be used. The stacked bar chart stacks bars that represent different groups on top of each other. The height of the resulting bar shows the combined result of the groups. However, stacked bar charts are not suited to datasets where some groups have negative values. In such cases, grouped bar charts are preferable." [Bar chart. Wikipedia]
The double bar graph template for the ConceptDraw PRO diagramming and vector drawing software is included in the Bar Graphs solution from the Graphs and Charts area of ConceptDraw Solution Park.