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Supporting Australian Mathematics Project: Middle years.

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Year 5

Statistics and Probability

Introduction to probability

Probability is a way of measuring, like length or area or weight or height. It measures the chance of a particular outcome occurring.

You might have considered simple and familiar outcomes involving chance and described whether they are 'likely' or 'unlikely', with some being 'certain' or 'impossible'.

We can compare probabilities on a scale using words like 'impossible' and 'certain' at each end of the scale, and words like 'not very likely', 'likely' and 'highly likely' to describe outcomes somewhere in between. For example, the chance of the Prime Minister walking into your classroom in the next five minutes is not very likely, but it is not impossible.

Number line marked from 'Impossible' on left to 'certain' on right
Detailed description

In the following pages we look at chance experiments, and describe the chance of particular events occurring using a number between 0 and 1.