How to calculate relative
frequency (%)
Definitions
Calculation
Example
Definitions
Frequency: how many times a property/
condition/event occurs within a
population or sample
 Relative frequency

◦ a proportion
◦ it is the value calculated by dividing the
frequency by the population or sample and
multiplying by 100
◦ It is written as a percent (%)
Calculation





There are 5 students with dyed hair in Miss.
Pitre’s grade 9 science class of 20 students.
 Relative frequency =
frequency ÷ population x 100
Frequency = 5
Population = 20
Relative frequency = 5 ÷ 20 x 100 = 25 %
25 % of Miss. Pitre’s grade 9 students have
dyed hair
Example

Hugo works on a farm. Out of his 50
cows, 15 of them are sick. What is the
relative frequency of cows that are NOT
sick. Show all your work.