Comparing Categories with Bar Graphs

Bar graphs are used to quickly demonstrate "which type had how much." Unlike a pie graph, there is no implication that a "whole" is being split up. For example, if I want to compare the average incomes of people who work in fire departments, police departments, and public schools, it would be very appropriate to use a bar graph – its not like these are the only three types of workers or that their average salaries are the only salaries that exist. A bar graph has a bar for each of the types, or categories, being considered, so this bar graph would have one bar for police, one for fire, and one for school. Each bar's length is determined by the information given, with larger numbers associated with larger salaries. If we find out that cops earn $62,000, firefighters earn $58,000, and teachers earn $45,000, one possible bar chart for that data follows: