this type or graph is used to show comparisons between values, with a bar representing each separate value. Categories or groups are commonly plotted on the horizontal axis (axis X) and a quantitative or numerical scale is plotted on the vertical axis (axis Y). Bar graphs are used to plot both continuous and discontinuous, or discrete, data.
advantages: show each data category in a frequency distribution, display relative numbers/proportions of multiple categories, summarize a large amount of data in a visual, easily intepretable form, make trends easier to highlight than tables do, estimates can be made quickly and accurately, permit visual guidance on accuracy and reasonableness of calculations, accessible to a wide audience
disadvantages: often require additional explanation, fail to expose key assumptions, causes, impacts and patterns, can be easily manipulated to give false impressions