Chart presentation of data using histogram, importance of chart presentation using histogram and their importance

A histogram is a statistical information screen that uses rectangles to display the frequency of data elements in successive equal-size numeric intervals. In the most common form of histogram, the independent variable is plotted along the horizontal axis and the dependent variable is plotted along the vertical axis. The data appears as colored or shaded rectangles of variable area. The illustration below is a histogram showing the results of a final exam given to a hypothetical class of students. Each scoring range is called by a bar of a certain color. If this histogram is compared with those of the classes of other years that received the same test of the same professor, conclusions could be drawn about the changes of intelligence among the students over the years. It is also possible to conclude the conclusions about the improvement or decrease of the teaching capacity of the teacher with the passage of time. If this histogram is compared with those of other classes of the same semester that have received the same final exam but have taken the course of different professors, one can draw conclusions about the relative competence of teachers.