Let’s now turn our attention to outliers – outliers are important pieces of information that spark deeper thinking into what lies beneath the surface.

Often, when we look at information, in whatever form be it tables, images, graphs and paragraphs, we should have a look at its composition – that is, what it’s made of. Usually, people accept the information that’s given as being complete. But, a step above this in terms of thinking, is asking the question – “mmm… this looks different. Should this bit of information be included or excluded from the rest?”

Those bits of information – the ones that are ‘different’ from the rest, are outliers.

What’s an outlier?

Outliers are points of information or ‘data’ points that aren’t ‘usual’ and there can be 1 or more outliers in any one set of information or data.

Outliers are interesting because they can:

• Can be excluded from the usual set of information – usually due to an ‘error’, or
• Can be included, perhaps due to providing an interesting point that may need further investigation.

Interestingly, there is no set rigid definition as to what is an outlier and much of it relies on our own judgement to isolate out a difference, kind of like doing an odd one out exercise. There are mathematical ways in which people can determine an outlier, but for the purpose of this thinking skills course, we’re going to use our ‘thinking skills’ to determine an outlier.

How to detect an outlier?

To detect an outlier:

1. Figure out the group or cluster of information pieces. This could be a group of scores that are similar to one another in some way e.g., regular interval, close proximity etc…
2. Find the odd one out. This can be over a time period; it can be in the same time period etc…
3. Determine if the outlier should be included or excluded and why. Look into the reason for the outlier.
4. Depending on whether you’re going to include or exclude the outlier/s, you then need to determine what you can say about the information presented. Does the inclusion of the outlier change what you’ll believe? Does the exclusion of the outlier change what you’ll believe? “Thinking” and judgement are required here.

Let’s see how to detect outliers now with a worked example.

Example Question/s

Watch video for explanation of the following question/s:

Question 1

The following represents English scores a person achieved every day over 10 days.

The teacher needs to determine a score to represent ‘essence’ of this student’s performance. How should he calculate this score?

A. Average of all the scores for both Test 1 & Test 2.
B. Average only the scores in Test 1 as Test 2 scores have outliers.
C. Average all scores except for the scores on Day 5.
D. Average all scores except for the score on Day 5 Test 2.

Question 2

A vaccine is being tested to immunise again JOVID-7, a virus that has reached pandemic proportions. So far, the vaccine has been tested on 50,000 people. Of the 50,000 people tested, 49,997 people reported no adverse effects, 2 people experienced severe allergies and 1 person contracted the JOVID-7 virus.

What can you say about the effectiveness of the JOVID-7 vaccine?

A. It is ineffective in protecting against JOVID-7 as you can still contract the virus.
B. It is largely effective in protecting against the JOVID-7 virus.
C. It should be redeveloped in full because it causes severe allergic reactions and may not work effectively.
D. It is important in preventing the spread of the virus.
E. Vaccinations aren’t necessary and your body should be able to naturally fight viruses.

Key Rules to remember

• You can find outliers by doing an ‘odd one out’ exercise and outliers can be present in many forms – e.g., images, graphs, paragraphs etc…
• There can be 1 or more outliers.
• You can exclude or include them – depending on what kind of information they present, and this likely changes the conclusions you end up with.
• Finding outliers and then understanding the information does take time so it’s important that you practice as it’s not a ‘cramming’ skill. Ask questions when you’re looking at information to help develop your thinking (actually, asking questions shows that you’re thinking more deeply!)

Practice time!

Now, it's your turn to practice.

Here’s a thought experiment #8.

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 8:

How do you know that you're not dreaming right now?

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.

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