1. We can present data in a graphical form as it is easier to see what is going
on, or to spot patterns, rather than looking at raw numbers in a table or in a
spreadsheet. Graphs are visual images which are quick and easy to read.
2. Raw data is collected and recorded in a table.
Eye colour
Blue Black Brown Grey Hazel Green
Class 8 3 15 2 4 0
One
A simple table is quite easy to read.
What is the most popular eye colour for this class?
3. There are 5 main types of graphs;
1. pictogram
2. bar chart.
3. comparative graph
4. pie chart
5. line graph
4. You used pictograms in ‘graphstart’. This is a
simple way of representing data with a
picture.
Y axis
This tells
us the
number
of pets.
X axis. This tells us the type of pets.
5. Can you think what the advantages and
disadvantages of a pictogram may be?
* Easy to read * simple data
* Quick * limited topics
* All languages * suits smaller numbers
6. A bar chart uses columns or blocks to show data values. This
type of chart is useful for showing bigger numbers and for
making quick comparisons.
Class 1
Y axis – 16
usually 14
12
represents 10
8
the values 6
tat change. 4
2
0
Children Blue Black Brown Grey Hazel Green
with eye Class 1
colour.
X axis – represents the category choices,
the data that does not change.
7. However, if you survey more classes, there is more
data to wade through.......
Blue Black Brown Grey Hazel Green
Class One 8 3 15 2 4 0
Class Two 10 1 14 6 0 1
Class Three 18 0 3 0 1 2
Class Four 14 3 9 5 7 0
Now which is the most popular eye colour?
It is much harder to spot the answers.
8. A comparative graph is used to compare sets
of data. It groups results for the same
category.
20
18
16
14
12 Class 1
10 class 2
8 class 3
6 class 4
4
2
0
Blue Black Brown Grey Hazel Green
9. A pie chart is a circle made from segments. Each segment
represents a proportion.
NOT that sort of PIE!!!!
10. THIS type of PIE!
The proportions of a pie chart are usually
shown as a percentage.
Class 1
Blue
Black This is called a
Brown legend – it uses a
Grey
colour code to
Hazel
Green
show the
categories.
11. Pie charts do not show exact values, but
percentages. They are really useful when
comparing a large sample with a small
sample.
It would be difficult, as a bar chart,
to compare class eye colour with a
top value of 30 children to a whole
school survey, where there will be
over 200 answers.
12. A line graph is used when the value being
measured is the same. It is similar to a bar
chart, but samples data at intervals.
Line graphs can track when values are
high or low. One example is a
weather chart, showing the sunshine
or rainfall for the year. Each month
would be an interval measure.
Business use line graphs to track their
sales.
13. Each graph type has it’s own advantages and
disadvantages. You need to think about your
purpose and audience before choosing
which style to use.
Can you remember the five main
types of graphs?
