Topics
14. Data
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Australia
Year 3

14.04 Mixed graphs

Lesson
Practice
Lesson

Are you ready?

Can you read information from a  column graph  or  picture graph  ? Look for keys or scales on a graph to help you understand what information is being presented.

Examples

Example 1

The column graph shows the number of each type of car fixed by the local mechanic.

A column graph shows the number of each type of car fixed by the local mechanic. Ask your teacher for more information.
a

Which car brand does the mechanic fix most often?

Worked Solution
Create a strategy

Choose the car brand with the tallest column.

Apply the idea

BMW has the tallest column, so the mechanic fixes BMW's most often.

b

How many Holden or Toyota cars did the mechanic fix in total?

Worked Solution
Create a strategy

Add the column heights for Holden and Toyota.

Apply the idea

Each tick on the left side of the graph represents two more cars. Holden's column has a height of 8, and Toyota's column has a height of 12.

\displaystyle \text{Total cars}\displaystyle =\displaystyle 8+12Add the two heights
\displaystyle =\displaystyle 20
Idea summary

For column graphs:

  • Check the scale of the graph. It may not always be 1.
  • If there is no column drawn, it represents a value of 0.

Look at the key on a picture graph to help you understand what each image is representing.

Different graphs

This video looks at how we can display the same data different ways using different graphs.

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Examples

Example 2

A group of children are going shopping and are deciding which shop to visit first. This table shows the shops the children like best.

A picture graph showing the shops children like best. Ask you teacher for more information.
a

How many children like the toy shop best?

Worked Solution
Create a strategy

Count the number of images next to Toy shop.

Apply the idea

There are 7 images next to toy shop. So there are 7 children that like the toy shop best.

b

Complete the column graph to show the same data as the table.

A blank column graph for types of shops and the number of children that like them. Ask your teacher for more information.
Worked Solution
Create a strategy

For each shop draw a column that has a height that is equal to the number of children that like that shop best.

Apply the idea
The column graph shows the number of children that like different shops. Ask you teacher for more information.
Idea summary

We can draw a new type of graph for the data shown in an existing graph. e.g. We can draw a column graph to show the same data from a picture graph.

Interpret graphs

This video shows us how to answer questions from graphs.

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Examples

Example 3

The pie graph below shows the results of a class survey where students were asked to nominate their favourite food:

The pie graphs shows results of class survey of their favorite food. Ask you teacher for more information.
a

Which was the most popular food?

Worked Solution
Create a strategy

Choose the largest area in the graph.

Apply the idea

The most popular food was pizza, since it takes up the most area in the graph.

b

Which food was as popular as noodles?

Worked Solution
Create a strategy

Choose the food with the same area as noodles.

Apply the idea

Burgers and noodles have the same size areas, so burgers are as popular as noodles.

Idea summary

When we use graphs, we need to figure out what it is telling us. We can use colours or pictures, or the size of a piece of the pie graph. We may also have labels on the graphs, so we need to check each graph to see what information we can use.

Outcomes

AC9M3ST02

create and compare different graphical representations of data sets including using software where appropriate; interpret the data in terms of the context

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