How Should We Get the Frequency for Each Class?

Frequency of a value is simply how many times it appears in the raw data. In the 100 mathematics marks, 40 occurs 3 times, 0 occurs once, 10 occurs once, 49 occurs 5 times, and so on — so the frequencies of 40, 0, 10 and 49 are 3, 1, 1 and 5. …