Topics
14. Data
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Stage 2

14.03 Column graphs

Lesson
Practice
Lesson

Are you ready?

Can you use a  picture graph  to answer questions?

Examples

Example 1

The pictograph shows the amount of hours a student spent this month doing homework for different subjects.

This image shows a pictograph on hours spent on homework. Ask your teacher for more information.
a

Which subject did the student do 5 hours of homework for?

Worked Solution
Create a strategy

Look for the subject with 5 clocks next to it.

Apply the idea

The answer is Mathematics.

b

Which subject did the student do the least amount of homework for?

Worked Solution
Create a strategy

Choose the subject that has the least clocks next to it.

Apply the idea

The answer is Geography.

Idea summary

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

Column graphs

This video shows shows how to construct a column graph to display data.

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Examples

Example 2

Amelia is looking at the cookbooks on the shelf at her grandparent's house. She counts how many there are of each type and put the results in the following table.

Type of Cookbook Number of Cookbooks
\text{Baking}2
\text{Italian}3
\text{Quick Meals }2
\text{Gourmet}4
a

Amelia wants to draw a column graph of this information.

How many columns will she need to draw?

Worked Solution
Create a strategy

Count how many different types of cookbooks there are.

Apply the idea

There a 4 different type of cookbooks.

Amelia needs 4 columns in her graph.

b

Draw the column graph that matches the table of information.

This image shows an empty graph about cookbooks. Ask your teacher for more information.
Worked Solution
Create a strategy

Use the table to know how high each column should go.

Apply the idea
The column graph shows the number of cookbooks for each type of cookbook. Ask your teacher for more information.
Idea summary

The height of the bars in a bar graph should match the numbers for each category in the table.

Interpret a column graph

This video shows how to read and answer questions about a column graph.

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Examples

Example 3

Miss Rodd recorded her students' favourite pets in the column graph below.

The column graph shows the number of each type of pet. Ask you teacher for more information.
a

Which type of pet is most popular?

Worked Solution
Create a strategy

Choose the pet that has the tallest column in the graph.

Apply the idea

The most popular type of pet means the most people picked it. The bird has most picked and tallest column in the graph.

The most popular type of pet is bird.

b

How many students picked a hamster as their favourite pet?

Worked Solution
Create a strategy

Look across to the number that matches the height of the bar for hamster.

Apply the idea

The height of the bar for hamster goes up to the line next to the number 6 on the left.

6 students picked hamster as their favourite pet.

c

How many students were surveyed in total?

Worked Solution
Create a strategy

Add the heights of each column.

Apply the idea
\displaystyle \text{Total student}\displaystyle =\displaystyle 6+8+2+6+14Add the heights
\displaystyle =\displaystyle 36Evaluate the addition
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.

Outcomes

MA2-18SP

selects appropriate methods to collect data, and constructs, compares, interprets and evaluates data displays, including tables, picture graphs and column graphs M

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