# 12.03 Picture graphs and dot plots

Lesson

## Ideas

Can you read  simple picture graphs  ? Graphs where each image represents 1 value, perhaps one person or object.

### Examples

#### Example 1

A class were asked to vote which sport they would like to play in their next lesson. The votes are shown in the picture graph.

Each image represents 1 vote.

a

How many students are in the class?

Worked Solution
Create a strategy

Each image represents 1 vote by 1 student. Count the images in the graph.

Apply the idea
b

A
Soccer
B
Worked Solution
Create a strategy

Choose the sport that has most images next to it.

Apply the idea

Idea summary

Picture graphs display data using pictures. It is important to read the key to understand what each picture represents.

## Picture graphs

This video uses an example of a picture graph to understand all the important elements, including the rows, columns, title and key, it also shows some strategies to be able to interpret and draw out information from a picture graph.

### Examples

#### Example 2

It’s "Back to school" time and a shop recorded the number of pens they sold this week.

a

How many pens were sold on Wednesday?

Worked Solution
Create a strategy

Count the number of pens for Wednesday and use the key.

Apply the idea

Each image of a pen represents 5 pens.

Wednesday has 4 pen images. So, 4 \times 5=20 pens.

The total number of pens sold on Wednesday is 20.

b

How many more pens were sold on Saturday than on Wednesday?

Worked Solution
Create a strategy

Subtract the number of pens sold on Wednesday from the number of pens sold on Saturday.

Apply the idea

Each image of a pen represents 5 pens.

Saturday has 5 pen images. So, 5 \times 5=25 pens.

5 more pens were sold on Saturday compared to Wednesday.

Idea summary

Another name for a picture graph is a pictograph. These graphs use pictures to represent data. One picture can have a value greater than 1, so we need to check the key to make sure we know what it represents.

## Dot plots

This video looks at dot plots and how they are used to display information.

### Examples

#### Example 3

Two dice are rolled and the total of the two numbers rolled is recorded. The results of 75 rolls are shown in the dot plot.

a

Which total is most likely?

Worked Solution
Create a strategy

Choose the number with most dots above it.

Apply the idea

The most likely total is 7.

b

How many rolls were 4 or less?

Worked Solution
Create a strategy

Add the dots above 4,3, and 2. Then multiply the sum by the number of rolls each dot represents.

Apply the idea

Since each dot represents 3 rolls, we need to multiply the sum by 3 to find the number of rolls.

Idea summary

Even though picture graphs and dot plots are different types of graphs, they both have information that we can find out. Using the headings, labels and key means we can find out the answers to questions about the data we have collected.

### Outcomes

#### VCMSP235

Construct, interpret and compare a range of data displays, including side-by-side column graphs for two categorical variables