The document discusses relative and cumulative frequency distributions. Relative frequency is calculated as the class frequency divided by the total frequency and expresses the percentage of the data that falls into each class. Cumulative frequency is the sum of a class frequency and all previous class frequencies and represents the running total. An example of calculating relative and cumulative frequencies is provided for age data on when people bought their first car and got their first job.

1. Mastering Statistics
Mean, Std Deviation, Variance, Z-score, Sampling

2. Relative and Cumulative Frequency Distribution
 Relative Frequency: the % of the data set that falls in a class
 R.F = (Class Freq)/ ∑ frequency, also called the sample size “n”
Age of people when buying 1st car
 R.F = 2/31 = 0.0645; as a percentage: RF = 0.0645*100 = 6.45
 R.F. = 7/31 = 0.2258; as % = 0.2258*100 = 22.58
Class Frequency Relative Frequency
15 - 18 2 6.45%
19 - 22 7 22.58%
23 - 26 4 12.9%
27 - 30 15 48.39%
31 - 34 3 9.68%
∑ = 31 The total will be 100%

3. Relative and Cumulative Frequency Distribution
 Cumulative Frequency: the sum of a frequency for a class and all previous classes
Age when get the first job
Class Frequency Cumulative Frequency
15 - 19 12 12
20 - 24 8 12 + 8 = 20
25 - 29 15 20 + 15 = 35
30 - 34 12 35 + 12 = 47
35 - 39 9 47 + 9 = 56
∑ = 56