Question

how to find cummulative frequency

Answer 1

The cumulative frequency is calculated by adding each frequency from a frequency distribution table to the sum of its predecessors. The last value will always be equal to the total for all observations, since all frequencies will already have been added to the previous total.

Answer 2

if you going on adding the frequency. example:

CI. F. CF
3-3.5. 6. 6
3.5-4. 4. 10
4-4.5. 6. 16
4.5-5. 8. 24
5-5.5. 7. 31