Cumulative relative frequency is a statistical calculation figured by adding together previously tabulated relative frequencies that makes a running total along a frequency table, according to Connexions. For instance, the first relative frequency of an occurrence is two out of 20 and the second relative frequency is five out of 20. The two frequencies are added together to make seven of 20, or 0.35 for a cumulative relative frequency.
Cumulative relative frequency has a maximum value of one. The purpose of the calculation is to keep a running total throughout a series of relative frequency calculations up to the final total. Frequency is the number of times a response is given. A relative frequency compares the given responses to the overall respondents of a survey or group.
A detailed example follows. Perhaps 50 students were asked a question with four different responses labeled "A" through "D." There are 13 marks for "A," 20 marks for "B," eight marks for "C" and finally, nine marks for "D." The cumulative relative frequency is calculated in a running total by adding 13/50 to 20/50, 8/50 and 9/50 for a total of 50/50. The decimal calculations are 0.26 added to 0.40, 0.16 and 0.18 to equal one. A running total of the cumulative relative frequency is listed as 0.26, 0.66, 0.82 and then finally one.
All this data is organized in a frequency table headed by columns that include a data value ("A" through "D"), frequency of the values chosen, relative frequency of the data and cumulative relative frequency. The final entry of one for the cumulative relative frequency indicates all of the data has been tabulated.