Title Y5 Maths 5015f - 2025 Week 17 Notes.pdf ✅

Page 2 A) Chance and Probability (from last week) The meaning of probability Probability is the chance of a particular outcome happening. We use special terminology: The following language is also commonly used in probability:  At least (e.g. ‘at least 3’ means 3, 4, 5, ...)  At most (e.g. ‘at most 7’ means ..., 5, 6, 7)  Or (e.g. ‘rolling an even number or a 5’ means rolling a 2, 4, 5, 6)  And (e.g. ‘rolling an even number and a prime number’ means rolling a 2) How do we know the chance or probability of something happening? In words the likelihood of something happening can be described as impossible, highly unlikely, unlikely, even chance, likely, highly likely and certain. In mathematics we can measure the probability of an occurrence or outcome as a number. Probability is always a number between or equal to 0 and 1. It can be written as a decimal, fraction or percentage. For example: 0.55 or 11/20 or 55% e.g. roll an even number, 2, 4, or 6, on a dice = Pr(rolling an even number) = 3/6 = 1⁄2 The symbol Pr( ) is used for probability