Histogram and frequency polygon

A histogram is a bar chart of data that have been grouped into a frequency distribution. It helps in identifying the area where most of the observations lie by simply looking at it.

Diagram

A frequency polygon is plotted by using the midpoint of each interval on the x-axis and the absolute frequency for that interval on the y-axis. It adds a degree of continuity to the representation of the distribution. It is a line chart.

Diagram

The cumulative frequency distribution can also be used to form frequency polygon. It allows us to see how many or what percent of the observations lie below a certain value.

Diagram

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