Relative Frequency

1
Relative Frequency

• How to calculate relative frequency

Noemi Navas Arranz
2
1. First of all, count the number of times that
each piece of data is repeated.
Football Team Tally marks Absolute Frequency Relative Frequency
Barça IIII IIII IIII
Real Madrid IIII II
Espanyol III
Total number of events
3

Football Team Tally marks Absolute Frequency Relative Frequency
Barça
Real Madrid II
Espanyol III
Total number of events
4

This is the absolute frequency.
Football Team Tally marks Absolute Frequency Relative Frequency
Barça 15
Real Madrid 7
Espanyol III 3
Total number of events
5
2. Next, count the total number of events.
Football Team Tally marks Absolute Frequency Relative Frequency
Barça 15
Real Madrid 7
Espanyol III 3
Total number of events
6

Football Team Tally marks Absolute Frequency Relative Frequency
Barça 15
Real Madrid 7
Espanyol III 3
Total number of events 25
7
3. Now, write a fraction for each piece of data.
Write the absolute frequency as the numerator and
the total number of events as the denominator.
Football Team Tally marks Absolute Frequency Relative Frequency
Barça 15
Real Madrid 7
Espanyol III 3
Total number of events 25
Numerator
15 25
Denominator
8

The fraction is the relative frequency.
Football Team Tally marks Absolute Frequency Relative Frequency
Barça 15 15 25
Real Madrid 7 7 25
Espanyol III 3 3 25
Total number of events 25
9
4. Then, divide the numerator by the denominator.
Use a calculator.
Football Team Tally marks Absolute Frequency Relative Frequency
Barça 15 15 25
Real Madrid 7 7 25
Espanyol III 3 3 25
Total number of events 25
1525
10
Round the result up or down to the nearest
hundredth.
Football Team Tally marks Absolute Frequency Relative Frequency
Barça 15 15 25
Real Madrid 7 7 25
Espanyol III 3 3 25
Total number of events 25
15250,60
11
The result of the fraction is also the relative
frequency.
Football Team Tally marks Absolute Frequency Relative Frequency Relative Frequency
Barça 15 15 25 0,60
Real Madrid 7 7 25 0,28
Espanyol III 3 3 25 0,12
Total number of events 25
12
5. What happens if you add up all the relative
frequencies?
0,60 0,28 0,12
1
Why is it 1?
Because the sum of all the relative frequencies
is the unit.
13
6. Look at these additions. Can you see any
differences?
0,60 0,28 0,12 1,00
0.60 0.28 0.12 1.00
The only difference is the use of different
symbols for the decimals the comma and the
point.
14
Catalan and Spanish speaking countries use the
comma for decimals.English speaking countries
use the point.
0,60 0,28 0,12 1,00
0.60 0.28 0.12 1.00
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Lets calculate the relative frequency!
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1. First of all...
Favourite food Tally marks Absolute Frequency Relative Frequency
Pizza
Vegetables
Fruit
Meat III
Pasta
Total number of events
17
Count the number of times that each piece of data
is repeated. This is the...
Favourite food Tally marks Absolute Frequency Relative Frequency
Pizza
Vegetables
Fruit
Meat III
Pasta
Total number of events
18

Absolute frequency
Favourite food Tally marks Absolute Frequency Relative Frequency
Pizza
Vegetables
Fruit
Meat III
Pasta
Total number of events
19

This is the absolute frequency
Favourite food Tally marks Absolute Frequency Relative Frequency
Pizza 12
Vegetables 7
Fruit 8
Meat III 3
Pasta 10
Total number of events
20

2. Next...
Favourite food Tally marks Absolute Frequency Relative Frequency
Pizza 12
Vegetables 7
Fruit 8
Meat III 3
Pasta 10
Total number of events
21
Count the total number of events.
Favourite food Tally marks Absolute Frequency Relative Frequency
Pizza 12
Vegetables 7
Fruit 8
Meat III 3
Pasta 10
Total number of events
22
So, how many people answered the question?
Favourite food Tally marks Absolute Frequency Relative Frequency
Pizza 12
Vegetables 7
Fruit 8
Meat III 3
Pasta 10
Total number of events
40
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3. Now...
Favourite food Tally marks Absolute Frequency Relative Frequency
Pizza 12
Vegetables 7
Fruit 8
Meat III 3
Pasta 10
Total number of events 40
24
Write a fraction for each piece of data. How?
Favourite food Tally marks Absolute Frequency Relative Frequency
Pizza 12
Vegetables 7
Fruit 8
Meat III 3
Pasta 10
Total number of events 40
25
Write the absolute frequency as the numerator and
the total number of events as the denominator.
Favourite food Tally marks Absolute Frequency Relative Frequency
Pizza 12
Vegetables 7
Fruit 8
Meat III 3
Pasta 10
Total number of events 40
Numerator
12 40
Denominator
26

The fraction is ...
Favourite food Tally marks Absolute Frequency Relative Frequency
Pizza 12 12 40
Vegetables 7 7 40
Fruit 8 8 40
Meat III 3 3 40
Pasta 10 10 40
Total number of events 40
27

The fraction is the relative frequency.
Favourite food Tally marks Absolute Frequency Relative Frequency
Pizza 12 12 40
Vegetables 7 7 40
Fruit 8 8 40
Meat III 3 3 40
Pasta 10 10 40
Total number of events 40
28
4. Then...
Favourite food Tally marks Absolute Frequency Relative Frequency
Pizza 12 12 40
Vegetables 7 7 40
Fruit 8 8 40
Meat III 3 3 40
Pasta 10 10 40
Total number of events 40
29
Divide the numerator by the denominator. Use
...
a calculator.
Favourite food Tally marks Absolute Frequency Relative Frequency
Pizza 12 12 40
Vegetables 7 7 40
Fruit 8 8 40
Meat III 3 3 40
Pasta 10 10 40
Total number of events 40
1240
30
Round the result up or down to ...
Favourite food Tally marks Absolute Frequency Relative Frequency
Pizza 12 12 40
Vegetables 7 7 40
Fruit 8 8 40
Meat III 3 3 40
Pasta 10 10 40
Total number of events 40
1240
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Round the result up or down to the nearest
hundredth.
Favourite food Tally marks Absolute Frequency Relative Frequency
Pizza 12 12 40
Vegetables 7 7 40
Fruit 8 8 40
Meat III 3 3 40
Pasta 10 10 40
Total number of events 40
12400,30
32
The result of the fraction is ...
Favourite food Tally marks Absolute Frequency Relative Frequency Relative Frequency
Pizza 12 12 40 0,30
Vegetables 7 7 40 0,18
Fruit 8 8 40 0,20
Meat III 3 3 40 0,08
Pasta 10 10 40 0,25
Total number of events 40
33
The result of the fraction is also the relative
frequency.
Favourite food Tally marks Absolute Frequency Relative Frequency Relative Frequency
Pizza 12 12 40 0,30
Vegetables 7 7 40 0,18
Fruit 8 8 40 0,20
Meat III 3 3 40 0,08
Pasta 10 10 40 0,25
Total number of events 40
34
5. What happens if you add up all the relative
frequencies?
0,30 0,18 0,20 0,08 0,25
1
Why is it 1?
Because the sum of all the relative frequencies
is the unit.
35
6. Work in groups.Order the steps of the process
to calculate the relative frequency.When you
finish write the numbers in your worksheet
individually.
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7. In groups, calculate the relative frequency
for your own data.