Cumulative Frequency Polygon

A frequency polygon whose vertices
represent the sum of all previous class frequencies
of the data. For example, if a frequency polygon had
vertices of 5, 8, 3, 7, and 10, the cumulative frequency polygon on the same
data would have vertices of 5, 13, 16, 23, and 33. As another example, a cumulative
frequency distribution for scores on a psychology test is shown below.