What is relative frequency?

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In order to find the relative frequency, we will use the frequency distribution table below and the following formula.

To find the relative frequency of a category, divide the frequency of that category by the sum of all frequencies.

We can express the relative frequency with a math formula.

Relative frequency of a category  
Frequency of that category / Sum of all frequencies

The table below is a frequency table of type of smartphone. Let us find the relative frequency for the categories you see in the able above.

Frequency distribution table
Relative frequency of  Android phone  
12 / 40
  = 0.3
Relative frequency of Window phone  
8 / 40
  = 0.2
Relative frequency of Iphone  
15 / 40
  = 0.375
Relative frequency of Amazon's fire phone  
5 / 40
  = 0.125

A relative frequency distribution is a table that shows the relative frequency for all categories as shown below.

Relative frequency distribution

Notice that the sum of the relative frequencies is always equal to 1.

The percentage of a category is found by multiplying the relative frequency of that category by 100.

Percentage of  Android phone = 0.3 × 100 = 30%

Relative frequency of  Window phone = 0.2  × = 20%

Relative frequency of   Iphone = 0.375 × 100 = 37.5%

Relative frequency of   Iphone = 0.125 × 100 = 12.5%

Since, the relative frequency of Window phone is 20%, we can conclude 20% of the people in the sample said that they own a Window phone.