Probability is a way of assessing chance, likelihood or risk. It may be quoted as a decimal, fraction or percentage. The probability of an impossible event is 0 and the probability of a certain event is 1. All other probabilities are between 0 and 1.

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## Glossary

### event

any set of possible outcomes of a statistical experiment

### fraction

A ratio of two numbers or polynomials.

### union

The union of two sets A and B is the set containing all the elements of A and B.

## This question appears in the following syllabi:

Syllabus | Module | Section | Topic |
---|---|---|---|

AQA GCSE (9-1) Foundation (UK) | P: Probability | P1: Frequencies in Tables and Trees | Basic Probability Problems |

CBSE IX (India) | Probability | Experiments | Repeated experiments |

CBSE X (India) | Statistics and Probability | Probability | Definition |

CIE IGCSE (9-1) Maths (0626 UK) | 8 Probability | C8.1 Calculating a Probability | Basic Probability Problems |

Edexcel GCSE (9-1) Foundation (UK) | P: Probability | P1: Frequencies in Tables and Trees | Basic Probability Problems |

GCSE Foundation (UK) | Probability | Probability | Basic problems |

OCR GCSE (9-1) Foundation (UK) | 11: Probability | 11.01d: Equally Likely Outcomes and Probability | Basic Probability Problems |

Universal (all site questions) | P | Probability | Basic problems |