Frequency Polygon
A frequency polygon is a graphical representation of data that displays the frequency of observations or occurrences within specific intervals or classes. It is constructed by connecting the midpoints of each interval or class with straight line segments, resulting in a polygonal shape. The heights of the line segments are determined by the corresponding frequencies.
Features of Frequency Polygon
- X-axis: Represents the variable being measured or observed, often referred to as the “independent variable.”
- Y-axis: Represents the frequency or count of observations within each interval, also known as the “dependent variable.”
- Intervals or classes: Divides the range of the variable into distinct groups or intervals.
- Midpoints: Represent the central value of each interval and are used as data points for constructing the polygon. They can be calculated by averaging the lower and upper boundaries of each interval.
- Line segments: Connect successive midpoints to form the polygon, providing a visual representation of the distribution of data.
Uses of Frequency Polygon
Frequency polygons are commonly used in statistics and data analysis to display the shape and distribution of numerical data. They provide a visual summary of the data, allowing for easy identification of patterns, trends, and key features. Frequency polygons can also be compared to other distributional graphs, such as histograms or frequency curves, to gain additional insights into the data.