Before entering fully into the definition of the term relative frequency, we are going to proceed to discover the etymological origin of the two words that give it its shape:
-Frequency, first of all, is a noun that derives from Latin, specifically from “frequentia”, which is the result of the sum of two lexical components of that language: the word “frequens, frequentis”, which can be translated as “full” or “multitude”, and the suffix “-ia”, which is used to indicate “quality”.
-Relative, secondly, it is a word that also comes from Latin. In its specific case, it emanates from “relativus”, which can be translated as “has a relationship”, and which is formed from the sum of three lexical components: the prefix “re”, which indicates “reiteration”; the verb “ferre”, which is synonymous with “carry”, and the suffix “-ivo”, which is used to show a “passive or active relationship”.

Is called frequency to the number of times an event is repeated in a certain period of time. It relativeOn the other hand, it is that which is not absolute or that is linked to something else. The idea of relative frequency It is used in the field of statistics. In this context, the frequency is known as number of times an event is repeated in a sample or in an experiment.

It is possible to differentiate between Absolute frecuency and the relative frequency. The absolute frequency refers to the number of times the phenomenon appears; the relative frequency, on the other hand, is obtained dividing the absolute frequency and the size of the sample.

Suppose that the statistical sample is formed with the prices from the bottle of a liter of beer of different trademarks:

\$ 40, \$ 42, \$ 40, \$ 40, \$ 40, \$ 45, \$ 48, \$ 50, \$ 48, \$ 42

The absolute frequency of \$ 40, for example, is 4, since in the sample there is 4 brands that offer the beer to \$ 40 (so \$ 40 appear 4 times).

The relative frequency of \$ 40, meanwhile, is 0.4. The data is obtained by dividing the absolute frequency (4) and the size of the entire sample (10). It is common for this data to be expressed as a percentage, for which you have to multiply the result by 100: 40%.

In the same sample, the absolute frequency of \$ 42 it is 2: there is 2 brands that, in the sample in question, sell the one-liter bottle of beer to \$ 42. Therefore, \$ 42 appear 2 times in the sample. With that figure, we can calculate the relative frequency of \$ 42, What is it 0.2 (2/10) or twenty% (0.2 x 100).

In the same way, we cannot ignore that there is what is known as a cumulative relative frequency. This is the quotient of dividing the accumulated frequency of a specific value by the total number of data that exist. It must be emphasized that it is measured in percentages and that it is represented as follows: Ni. However, it can also be represented with Fi.

To all the above, we have to add that this accumulated relative frequency of each value will always be greater than the usual relative frequency. The only exception to this rule will be in the case of the lowest value.