This type of graph shows continuous data
(such as age). A histogram breaks the range of
the continuous variable into equal intervals, for
example 56 years. The graph also displays a
count (or a percentage) of observations that fall
into each interval; for example, the percentage
of students who own a dog.
Histograms can help answer questions such as
'Are 12 year olds more likely to own a dog than
10 year olds?'
Bar graphs show data grouped by categories
(such as 'cat owners' or 'dog owners'). The
people surveyed can select more than one
category.
Each bar on a bar graph shows the frequency
of a response.
Bar graphs can help answer questions such as
'Do more people with black hair own cats or
dogs?'
Pie graphs show data grouped by categories.
The people surveyed can nominate only one
category. Pie graphs are only useful when there
are a small number of a categories.
Pie graphs can help answer questions such as
'Do more people have blue eyes or brown?'
Row  Person  Age  Sport  Team 

Row  Person  N  S  T  B  FS  FO 

Row  Person  Artistic activity 

Continuous data describes results that
have no gaps or overlaps.
Age is an example of continuous data
because the age of each person
surveyed must be between zero and
the age of the oldest person in the
world. There are no gaps in the
numbers since every age is possible.
There are no overlaps since noone is
more than one age.
Frequency is how many times one
answer was given during a survey.
If 34 people answered 'Yes' to a
question, the frequency for that
answer would be 34.
Evidence is a collection of facts that suggest
the truth.
Surveys don't tell us exactly what the truth is,
because only a sample of people are
interviewed. Also, some people may not
answer honestly or accurately.
However, surveys can point to the truth by
providing evidence about what people do or
think about a particular topic.
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Conditions of use 
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