# NCERT Class 9 Maths Formula CBSE Board Sample Problems Part 14

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## 14. Probability

S.No | Term | Description |

1 | Empirical probability | It is a probability of event which is calculated based on experiments |

2 | Empirical Probability = Example: A coin is tossed 1000 times; we get 499 times head and 501 times tail, So empirical or experimental probability of getting head is calculated as Empirical probability depends on experiment and different will get different values based on the experiment | |

3 | Important point about events | If the event A, B, C covers the entire possible outcome in the experiment. Then, |

4 | Impossible event | The probability of an event (U) which is impossible to event occur is O. Such an event is called an impossible event P (U)=O |

5 | Sure or certain event | The probability of an event (X) which is sure (or certain) event to occur is 1. Such an event is called a sure event or a certain event P(X) =1 |

6 | Probability of any event | Probability of any event can be as |