What is the cumulative frequency of the modal class of the following distribution?


Class



3 - 6



6 - 9



9 - 12



12 - 15



15 - 18



18 - 21



21 - 24



Frequency



7



13



10



23



4



21



16


Here, the maximum class frequency is 23.

The class corresponding to this frequency is the modal class. modal class = 12 - 15


Lets form a table.


CLASS



FREQUENCY(fi)



Cf



3 - 6



7



7



6 - 9



13



7 + 13 = 20



9 - 12



10



20 + 10 = 30



12 - 15



23



30 + 23 = 53



15 - 18



4



53 + 4 = 57



18 - 21



21



57 + 21 = 78



21 - 24



16



78 + 16 = 94



TOTAL



94




Since, modal class = 12 - 15, the corresponding cumulative frequency is 53.


14