Prime objective of this lecture is to present on Bar Graphs and Histograms. By this lecture you will able to learn about bar graph, double bar graph and Histogram. A Bar Graph (also called Bar Chart) is a graphical display of data using bars of different heights. Bar Graphs are good when your data is in categories (such as “Comedy”, “Drama”, etc). A bar graph can be used to display and compare data. The scale should include all the data values and be easily divided into equal intervals.