This document discusses grouping discrete data and calculating statistics like the mode, mean, and frequency. It provides an example of grouping the number of goals scored in soccer matches to find the mode of 3 goals. Another example calculates the mean shoe size from a survey by tallying shoe sizes into a frequency table and dividing the total by the number of participants.

1. October 4, 2012
Grouping Data
2. Grouping discrete data.
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2. Explanation October 4, 2012
Herecan alsoof the number of goals out the mean. of
You is a list use this table to work scored in each
the first 20 matches involving West Ham United, in the
2005 – 2006 season. Multiply
each
4 0 3 4 4 3 0 2 3 3number 3 5 3 6 2 2
2 1 2 3 of
You can often see a pattern more easily, itsthe data is
goals by if
grouped in some way. frequency,
Number of goals Frequency then add the
From this table it is easy
0 2 results.
1 1 to identify the mode, the
2 5 number of goals scored in
3 3 7 7 a game with the greatest
4 3
5 1 frequency.
6 1 The mode is 3.
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3. Explanation October 4, 2012
You can also use this table to work out the mean.
Number of goals Frequency Goals × Frequency Multiply
0 2 0
1 1 1
each
2 5 10 number of
3 7 21 goals by its
4 3 12
5 1 5
frequency,
6 1 6 then add the
Totals 20 57 results.
Mean = 57 ÷ 20 = 2.85
You can check this by adding up the original list of goals
scored and dividing the answer by 20.
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4. Explanation October 4, 2012
This can also discrete table to work out the mean.
You is called use this data.
This is because you can only
Number of goals Frequency
score goals in whole, counted
0 2
numbers.
1 1
You cannot score 2.85 goals
2 5
3 7
in a game!
4 3
The mean, however can be
5 1
a number it is not possible
6 1
to score in real life.
Other examples of discrete data would be:
The number of people who live in your household.
The number of students in your class with brown eyes.
The number of blue cars in the car park.
The number of fish in the sea.
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5. Explanation October 4, 2012
A survey of the shoe sizes of 50 people produced the
What is the modal group? Shoe size 3.
following results.
Tally the results to produce a frequency table.
3 5 6 13 2 Shoe size Tally Frequency
12 4 7 2 8 2 4
2 8 11 5 6 3 10
4 2
3 7 9 9 11
5 7
3 7 12 6 8 6 6
6 10 3 3 5 7 3
5 4 6 3 3 8 5
9 5
10 13 8 6 9
10 2
2 3 5 5 3 11 2
3 5 9 8 9 12 2
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6. Explanation October 4, 2012
Multiply shoe size by frequency, and total the column.
Total the frequency column.
Mean shoe size = 315 = 7.3
50
Shoe size Tally Frequency Size × Freq.
2 4 8
3 10 30
4 2 8
5 7 35
6 6 36
7 3 21
8 5 40
9 5 45
10 2 20
11 2 22
12 2 24
50 315
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7. Example October 4, 2012
Calculate the mean number of children in each house on
Bury Road.
Frequency ×
No. of Children Frequency
No. of children
0 4 0
1 6 6
2 5 10
3 7 21
4 1 4
5 2 10
Total 20 51
Mean Children per house = 51 = 2.55
20
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