Draw a frequency polygon for the following frequency distribution:
The given frequency distribution table is as below:
This table has inclusive class intervals and so these are to be converted into exclusive intervals (i.e. true class limits).
These are (0.5-10.5), (10.5-20.5),(20.5-30.5),(30.5-40.5),(40.5-50.5), and (50.5-60.5).
In order to draw a frequency polygon, we need to determine the class marks. Class marks of a class interval = upper limit+lower limit2
Take imaginary class interval (-9.5 – 0.5) at the beginning and (60.5 – 70.5) at the end, each with frequency zero. So we have the following table
|Class intervals||True class Intervals||Class marks||Frequency|
Now, take class marks along x-axis and their corresponding along y-axis.
Mark the points and join them.
Thus, we obtain a complete frequency polygon as shown below: