### Possible Answer

Cumulative frequency is actually the sum of all frequencies upto that level, if u see the picture, in first level its 1. in the second level the frequency is 0. so adding this we get the cumulative frequency 1, and next level the frequency is 1 so add this to the cumulative frequency ... - read more

Why use cumulative frequency? Cumulative frequency gives the total number of events that occurred up to some value. Perhaps I want to show the number of accidents that occur in a year by the drivers age. - read more

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