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What is a culmulative frequency polygon and how can we draw the it?

A cumulative frequency polygon is a diagram representing grouped numerical data in which cumulative frequencies are plotted against upper class boundary. The resulting points are joined by straight line segments to form a polygon, and it starts at the point on X-axis corresponding to the lower boundary.

Procedure
Step 1

Mark the lower boundary of the first class interval along the horizontal axis.

Step 2

Mark the upper boundary of each class interval along the horizontal axis.

Step 3

For each class interval, plot the cumulative frequency against the upper boundary of the interval.

Step 4

Join these points to form a line graph.

Step 5

Smooth the graph, if you can, so that it forms an "s-shaped " curve, which should look something like the graph below.


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