A bar chart or bar graph is a chart with rectangular bars with lengths proportional to the values that they represent. The bars can be plotted vertically or horizontally. A vertical bar chart is sometimes called a column bar chart.
Bar charts provide a visual presentation of categorical data. Categorical data is a grouping of data into discrete groups, such as months of the year, age group, shoe sizes, and animals. In a column bar chart, the categories appear along the horizontal axis; the height of the bar corresponds to the value of each category.
Bar charts can also 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.
A bar chart is very useful for recording certain information whether it is continuous or not continuous data. Bar charts also look a lot like a histogram, however bar charts have spaces between columns (unlike histograms) as values are independent of each other.
The first bar graph appeared in the 1786 book The Commercial and Political Atlas, by William Playfair (1759-1823). Playfair was a pioneer in the use of graphical displays and wrote extensively about them.
Famous quotes containing the words bar and/or chart:
“I am of course confident that I will fulfil my tasks as a writer in all circumstances—from my grave even more successfully and more irrefutably than in my lifetime. No one can bar the road to truth, and to advance its cause I am prepared to accept even death. But may it be that repeated lessons will finally teach us not to stop the writer’s pen during his lifetime? At no time has this ennobled our history.”
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—Eleanor Roosevelt (1884–1962)