We’ve seen how data can be presented in various ways: tables, bar charts and line charts. Let’s now look at when there are charts that combined various other charts together (e.g., like a bar and line chart) and let’s examine in detail a type of chart that you may have before, called a ‘pie chart’.

This checkpoint is divided into two parts: pie charts and combined charts.

PART 1 – Pie charts

What’s a pie chart?

A pie chart shows the “division” of data. We’ve seen previously that bar charts generally “tally” and line charts show “trends”. Now that you’re a bit more advanced, we’re going to look at when data should be displayed in certain graphs.

Let’s discuss (see video) the two graphs below that depict the same data. Why is a pie chart not really useful here?

Source: Data.gov.au is licensed with CC BY 4.0.

Now, let’s look at a pie chart as a depiction of data that’s useful. Why is using a pie chart in this instance better than using a bar chart or line chart? (Watch the video).

Source: Data.gov.au is licensed with CC BY 4.0.

Additionally, some charts look like pie charts but are not. Like this one below. Watch the video to find out why.

Source: Data.gov.au is licensed with CC BY 4.0.

Now that we’ve looked at pie charts, here are things to note if you want to do well in your exam when you’re faced with a question that includes a pie chart:

• What’s the WHOLE?
• What are the parts of a whole (shown visually in slices of the ‘pie’ and how do these relate to the whole)? The common parts of a whole you need to know are as follows:

What the video to see a full discussion on ‘whole’ and common parts you need to know.

Now, let’s see if we can work backwards using our newly acquired skills in looking at pie charts. Match up each of the parts.

How to answer questions relating to pie charts

Keeping in mind that the ‘usefulness’ in pie charts is in seeing how things are “divided”, here are some guidelines to help you answer questions where there are pie charts.

1. Look at the wording carefully so that you’re sure of what’s being ‘divided’.
2. Know your whole and parts – does your whole change? If so, how do that parts change and how are they recalculated?
3. Refer to general visual division so you can quickly identify.
4. Interpret and select your answer.

Let’s see it in action now with a worked example.

Example Question/s

Watch video for explanation of the following question/s:

Question 1

The above pie chart was supposed to represent the data shown in the side table. However, due to an input error, one type of pet was missing from data that generated the above pie chart. What pet type was missed due to this input error?

A. Rabbits
B. Cats
C. Turtles
D. Dogs

Question 2

Source: Data.gov.au is licensed with CC BY 4.0.
Assume that DTESB’s total expenses for the coming year were the same as the year shown in the above chart. However:

• All grants and subsidies payments have been cut
• An $5 million cut from employee costs due to the use of artificial intelligence.

Which one of the following pie charts would best represent DTESB’s coming year expenses? Please note that the colouring between the charts above and below is consistent.

Key Rules to remember

• Pie charts show ‘division’, therefore, know your whole and how to changes and how this affects your parts.
• Know the key visuals in terms of ‘pie slices’ – 25%, 50%, a third, a fifth (20%), an eighth.

PART 2 – Combined charts

What are combined charts?

When people see combined charts, they think that it’s much more complicated than a simple chart. Sometimes you might see bars with lines, scatter plots with lines etc…

In many ways, combined charts are difficult because they include various charts together so that people can see sets of information relative to other information. This helps to make conclusions stronger (in general).

However, reading one isn’t too difficult. All you have to do is:

• Consider each one separately (we did this in the previous checkpoints).
• See how they relate to one another.

Let’s look at one now. What insights can be found from the below chart? (Watch the video for a full discussion).

Source: Data.gov.au is licensed with CC BY 4.0.

How to answer questions relating to combined charts

Similar to answering questions where there are bar or line charts, to answer questions relating to combined charts:

1. Know your requirement.
2. Orientate at a basic level: heading, units, axes – while noting any additional axes!
3. Identify separate graphs (sharing the same space) and interpret each one individually first – what is it trying to show us? Use the learning gained from previous checkpoints for your relevant chart.
4. Relate one chart to the next to draw any relationship. Is there a dependency relationship? No relationship? Positively correlated? Negatively correlated?
5. Interpret and obtain insight relevant to your question.

Let’s see it in action now with a worked example.

Example Question/s

Watch video for explanation of the following question/s:

Source: Data.gov.au is licensed with CC BY 4.0.

Which of these is correct?

A. The amount of wheat produced in that year determines how much grain can be exported in that same year.
B. The amount grain exported above production in 2006-07 must have been taken from the surplus wheat produced in 2005-06.
C. There are seven years in which there is a surplus of wheat produced over the quantity of grain exported.
D. Exports of grains increase and decrease with time independently without any influence from production.

Key Rules to remember

• Separate out the independent charts, analyse and then see how they relate to one another. Is there a dependency relationship? No relationship? Positively correlated? Negatively correlated?
• Check the series of data with the axis – sometimes, it may use a different axis and this can be a source of confusion.

Practice time!

Now, it's your turn to practice.

Here’s a thought experiment #15.

Remember, there is no formal answer and this experiment is provided to help stimulate your creativity and critical thinking (a ‘thought experiment’ is provided at the end of every checkpoint except checkpoint 18).

Thought experiment 15:

Is there such a thing as ‘ultimate fairness’ – or is what’s ‘fair’ dependent on each person’s perspective?

Take your time to work through this thought experiment as it is not assessed and provided to help develop your deeper thinking skills. Think about various components of the question. What questions will you ask yourself and how do you answer your questions?

Now, let’s turn to the checkpoint questions.

Click on the button below and start your practice questions. We recommend doing untimed mode first, and then, when you're ready, do timed mode.

Every question has two solutions videos after you complete the question. The first is a quick 60 second video that shows you how our expert answers the question quickly. The second video is a more in-depth 5-steps or less explainer video that shows you the steps to take to answer the question. It's really important that you review the second video because that's where you'll learn additional tips and tricks.

Once you're done with the practice questions, move on to the next checkpoint.

Now, let’s get started on your practice questions.

---