The histogram is used to display in bar graph format measurement data distributed by categories.
A histogram is used for the following:
Making decisions about a process, product or procedure that could be improved after examining the variation. For example, should the school invest in a computer-based tutoring program for low achieving students in Algebra after examining the grade distribution, are more shafts being produced out of specifications that are too big rather than too small?
Displaying easily the variation in the process. For example, which units are causing maximum difficulty for students, is the variation in a process due to parts that are too long or parts that are too short?