The cumulative frequency of a value of a variable is the number of values in the collection of data less than or equal to the value of the variable.
For example: Let the raw data be 2, 10, 18, 25, 15, 16, 15, 3, 27, 17, 15, 16. The cumulative frequency of 15 = 6 (Since, values ≤ 15 are 2, 10, 15, 15, 3, 15).
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