Probability - AQAProbability and the probability scale

Probabilities can be written as fractions, decimals or percentages on a scale from 0 to 1. Knowing basic facts about equally likely outcomes can help to solve more complicated problems.

Part ofMathsProbability

Probability and the probability scale

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Probability is about estimating or calculating how likely or 'probable' something is to happen. The chance of an event happening can be described in words, for example ‘certain’, ‘impossible’ or ‘likely’.

In maths, probabilities are always written as , or with values between 0 and 1.

The probability scale

An outcome that is impossible has a probability of 0 and an outcome that is certain has a probability of 1. This means probabilities cannot be bigger than 1. This can be shown on a probability scale.

Scale of probability from 0 to 100.