Both the frequency and relative frequency give us information about the occurrence of the data values in a given set of data. While the frequency gives us the absolute value of the number of times a particular data value is repeated, the relative frequency tells us about the occurrence of a data value in the form of a fraction or percentage.
Suppose we are given the following set of data:1, 1, 1, 3, 4, 5, 5, 8, 9, 12
Here the value 1 has a frequency of 3 because the value 1 occurs 3 times in the above set of data. On the other hand since 1 occurs three times out of ten, then expressing it in the form of a proportion/fraction we conclude that 1 has a relative frequency of 3/10 = 0.3 (that is, 30% in percentage form).
Difference between Frequency and Relative Frequency:
|1. The frequency is the number of times a particular value occurs in a given set of data.||1. The relative frequency the proportion of occurrence of a particular value occurs in a given set of data.|
|2. The frequency can be equal to any whole number 0, 1, 2,…||2. The relative frequency is always a number lying between 0 and 1.|
|3. On adding all the frequencies we get the total number of values in the given set of data.||3. The sum of all relative frequencies adds up to 1.|
|4. If we know whether a given value is occurring an abnormally large number of times we need to compare its frequency with the other frequencies.||4. If we know whether a given value is occurring an abnormally large number of times we only need to know the relative frequency of that data point. There is no need to compare its relative frequency with the other relative frequencies.|
|5. We can visualize the frequencies by plotting line graphs, ogives, histograms, etc. Thus there are many ways to graphically represent frequencies of a given data set.||5. We only have one way to visualize relative frequency – that is, by drawing a pie chart.|