50 now our table looks like this: Class Lower Upper f cf rf crf 0.16 0.16 0.2 0.12 0.36 Finally, we fill in the "crf" column. Remember that "crf" stands for cumulative relative frequency. Like you got cf by adding the values in the f column, you get crf by adding up the values in rf column. The crf value for Class 1 will always be the same as the rf value for Class 1: To find the crf value for Class 2, you just add the relative frequencies (rf} from Class 1 and Class 2: To find the crf value for Class 3, you just add the relative frequencies (rfj from Class 1, 2 and 3: To find the crf value for Class 4, you just add the relative frequencies (rf} from Class 1, 2, 3 and 4: To find the crf value for Class 5, you just add the relative frequencies {H} from Classes 1 - 5