Loading please wait

The smart way to improve grades

Comprehensive & curriculum aligned

Try an activity or get started for free

Find Outliers in Scatter Graphs and Frequency Distributions

In this worksheet, students will practise finding the outliers in scatter graphs and frequency distributions.

'Find Outliers in Scatter Graphs and Frequency Distributions' worksheet

Key stage:  KS 4

Year:  GCSE

GCSE Subjects:   Maths

GCSE Boards:   AQA, Eduqas, Pearson Edexcel, OCR,

Curriculum topic:   Statistics

Curriculum subtopic:   Statistics Analysing Data

Difficulty level:  

Worksheet Overview

When you are dealing with data, there is sometimes a need to exclude certain values.

If you were finding the average height of people in a reception class one day, you wouldn't include the teacher, as that would distort the data.

In maths, these are called outliers and there are two places you could meet them.


Scatter graphs

It is quite easy to spot outliers in a scatter graph, they're just the ones that don't fit into the pattern:


Outliers in scatter graphs


We can see that for these two scatter graphs, the points that are circled don't fit into the pattern of the rest - these would be outliers.


Frequency distributions

This is a bit more mathematical. There are other activities on how to find the interquartile range (IQR) and median of a distribution, so if you're not too sure about these, it would be a good idea to have a look at one of those before tackling these questions.


Outliers are defined as being:

Greater than the upper quartile (UQ) + 1.5 x IQR

Less than the lower quartile ( LQ) - 1.5 x IQR



A data set has a lower quartile of 20 and an upper quartile of 28.

Find the limits for the outliers.


Step 1: Find the IQR

IQR = UQ - LQ = 28 - 20 = 8


Step 2: Find 1.5 x IQR

1.5 x IQR = 1.5 x 8 = 12


Step 3: Find the limits for the outliers

UQ + 1.5 x IQR = 28 + 12 = 40

LQ - 1.5 x IQR = 20 - 12 = 8


This means that any numbers below 8 or above 40 in the distribution are outliers.


Question time!

What is EdPlace?

We're your National Curriculum aligned online education content provider helping each child succeed in English, maths and science from year 1 to GCSE. With an EdPlace account you’ll be able to track and measure progress, helping each child achieve their best. We build confidence and attainment by personalising each child’s learning at a level that suits them.

Get started

Try an activity or get started for free

  • National Tutoring Awards 2023 Shortlisted / Parents
    National Tutoring Awards 2023 Shortlisted
  • Private-Tutoring-WINNER-EducationInvestor-Awards / Parents
    Winner - Private Tutoring
  • Bett Awards Finalist / Parents
  • Winner - Best for Home Learning / Parents
    Winner - Best for Home Learning / Parents