Explain why the mean is useful and when it is not appropriate
Lesson details
Learning outcome
I can explain why the mean is useful and when it is not appropriate representation of a set of data
Key learning points
- If there is an outlier or value that does not fit with the set the mean average will not be appropriate.
- In some contexts, the mean average does not give a useful representation of a set of data,
Keywords
Mean average - The mean average is a single number expressing the typical value in a set of data. It is calculated by finding the total of the set of data and dividing by how many values there are.
Set of data - A set of data is collection of facts, such as numbers, words, measurements, observations or even just descriptions of things.
Outlier - An outlier is a value that lies outside. It is much smaller or larger than most of the other values in a set of data.
Common misconception
You need to look carefully at a set of data to make sure that the values are reasonable and that calculation of the mean average will give a value that is useful when describing the set and comparing.
Encourage pupils to look carefully at a set of data, identifying values that look unusual and thinking about the impact that they will have if the mean average is calculated. An outlying value in one set of data may be reasonable in another set.
Teacher tip
Other averages will be covered at secondary school and this lesson aims to raise awareness that the mean average is not always a useful value when considering and comparing data. Mean averages that are not whole numbers are included in this lesson.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1. = 81 ÷ 9
Q2.Give your answer as a decimal. 45 ÷ 4 =
Q3.If the mean average of a set of data is 7, what can the total value not be?
Q4.Lucas records how many times children change their books during the week in Oak Class and Willow Class. Match the correct mean average to the class.
4
5
Q5.Here are some spelling test scores. Laura: 12; Lucas: 10; Sofia: 8; Jun 2 Lucas says that mean average is 7 because 32 ÷ 4 = 7. Is Lucas correct?
Q6.Calculate the mean average goal difference for the Oak hockey team.
Assessment exit quiz
6 Questions
Q1.An outlier is a value that lies outside. It is much _______ or ______ than most of the other values in a set of data. Select two missing words to complete the definition.
Q2.Identify the outlying values in this set of data.
Q3.Look at the data. Laura says we must include 0 when calculating the mean average. Lucas disagrees and says that it should not be included in this example. Who is correct?
Q4.Match the problem to show whether working out the mean average would be helpful or not.
How long it takes for children to read 100 words.
What size jumpers children wear from Year 1 to Year 6
Q5.Calculate the mean average of the spelling test scores without the outlying value.
Q6.Calculate the mean average of goals scored per match without the outlying value. The mean average is .
To help you plan your 6 maths lesson on: Explain why the mean is useful and when it is not appropriate, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 6 maths lesson on: Explain why the mean is useful and when it is not appropriate, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
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Explore more key stage 2 maths lessons from the Mean average unit, dive into the full primary maths curriculum, or learn more about lesson planning.