Question

Less than 20 - 0
Less than 25 - 30
Less than 30 - 75
Less than 35 - 127
Less than 40 - 165
Less than 45 - 185
Less than 50 - 197
How to draw frequency polygon for this information?

Answer 1

You must be given the frequencies of the Class Intervals, and these class intervals which you changed to Less than type is wrong.

It must go like this:

Less than 20

Less than 30

Etc

Change the frequencies of then Class intervals to Cumulative frequencies.

And then you must get the coordinates of these points eg

Less than 20. Cf: 10. Then coordinates are (20,10)

Then you can plot them in a graph