aaa Bar Graph - A graph consisting of parallel, usually vertical bars or rectangles with lengths proportional to the frequency with which specified quantities occur in a set of data. Also called bar...
bar graphs are used to compare different data. a line graph is used to see the changes over a period of time of a specific data. a circle graph is used to represent a part to a whole relationship.
well...not sure if you know this but bar graphs already ARE bar graphs, the good news is you don't have to transform them... so half your work is already done XD!