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.

A set of data is a collection of facts, such as numbers, words, measurements, observations or even just descriptions of things.

Explain how the mean changes when the total quantity or number of values changes

Maths

In this unit pupils will learn how to calculate the mean of a set of data and use the mean to make comparisons between two sets of information. In the future unit pupils will calculate and compare the mean, median and mode of a set of data.

In the prior unit pupils interpreted and constructed pie charts and line graphs and used these to solve problems. They read scales and made links to fractions, angles, percentages and understanding proportional relationships. In this unit pupils will learn how to calculate the mean of a set of data and use the mean to make comparisons between two sets of information.

Mean average

What is the missing mean average in the table? Can you reason about the missing value without doing the calculations again?

The table shows the number of cards each child currently has, the current total and mean average. Work out the mean average if Lucas gave one of his cards to Jun. 

The table shows the number of cards each child currently has, the current total and mean average. Work out the mean average if Aisha loses 5 of her cards. 

The table shows the number of cards each child currently has, the current total and mean average. Work out the mean average if Lucas gains an extra 10 cards. 

Six children are playing a card game. What total number of cards could the children have so that the mean average would be a whole number?

Some children play a card game. What number of cards could the children have so that the mean average would be a whole number when 4 or 5 of them are playing? 

What is the difference between 12 and 15? 

The data shows the number of pages read by four children. What is the mean average number of pages? Jun: 6; Sam: 5; Alex: 11; Jacob: 2

The data shows the number of pages read by four children. What is the mean average number of pages? Jun: 9; Sam: 0; Alex: 12; Jacob: 5

Lucas says: 'Sofia didn’t read anything so we can find the average pages read for all of us without her data.’ Is he correct?

This lesson will soon be taken down.

Explain how the mean changes when the total quantity or number of values changes

Lesson outcome