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neurologyYou need to know

• Probability is a measure of how likely an event is to occur, and is expressed as a number between 0 (impossible) and 1 (certain).
• The probability scale can be described using words such as 'impossible', 'unlikely', 'even chance', 'likely', and 'certain'.
• Probabilities can also be expressed as fractions, decimals, or percentages.
• An experiment or trial is a process performed to produce an outcome.
• An outcome is one possible result of an experiment or trial.
• An event is a set of one or more outcomes.
• The sample space is the set of all possible outcomes of an experiment or trial.
• For a finite sample space of equally likely outcomes, the probability of an event is calculated as `\text{Probability of event} = \frac{\text{number of outcomes in the event}}{\text{total number of outcomes in the sample space}}`.
• The sum of the probabilities of all outcomes in a sample space is 1.
• The probability of an event not happening is equal to 1 minus the probability of the event happening.

• Use the probability scale to describe the likelihood of events, both with words and by placing events at the correct position on a 0 to 1 number line.
• List all possible outcomes for a given experiment or trial, such as rolling a die or flipping a coin.
• Decide whether the outcomes in a finite sample space are equally likely before calculating probability by counting outcomes, including in simple situations where outcomes are not equally likely.
• Calculate the probability of a single event by counting the favourable outcomes and the total number of possible outcomes when all outcomes are equally likely.
• Calculate the probability of an event not happening, using the fact that probabilities sum to 1.