A bar graph is also called a bar chart and consists of bars that are separated from each other. It either uses horizontal or vertical bars to show comparisons among categories. The bars can be rectangles, or they can be rectangular boxes (used in three-dimensional plots). One axis of the graph represents the specific categories being compared, and the other axis shows a discrete value. In this graph, the length of the bar for each category is proportional to the number or percent of individuals in each category. Some bar charts show bars clustered in groups of more than one (grouped bar graphs), and others depict the bars divided into subparts to show cumulative effect (stacked bar graphs). A bar graph is a better choice than a line graph or histogram because this data is categorical rather than continuous. Also, it is appropriate to compare the relative size of the categories. It is to be noted that the bar graphs that are organized from highest to lowest are called Pareto charts.