A cumulative frequency polygon is a plot of the cumulative frequency against the upper class boundary with the points joined by a line segment. An ogive is any continuous cumulative frequency curve, including cumulative frequency polygons. A cumulative frequency polygon displays cumulative frequency on the x-axis and class marks on the y-axis.
Frequency polygons are line graphs joined by all the midpoints at the top of the bars of histograms. Frequency polygons illustrate the shape of the distribution of the data. The endpoints of a frequency polygon lie on the x-axis. To construct a frequency polygon, a bar graph or histogram must first be drawn. Then, a line graph is drawn over the bar graph. Frequency polygons and histograms are similar in that they show the same information but in a different manner. When comparing two different sets of data, it is often easier to display the data using a frequency polygon versus a histogram. Some examples of data illustrated in a frequency polygon are the number of vehicles passing through a particular point in a route, the number of hours a student in a class spends studying and the display of exam scores between two different sets of students.