Final answer:
An event in probability is a subset of outcomes within the sample space of an experiment, and it is represented by uppercase letters such as 'A'. The probability of an event indicates its likelihood of occurrence, ranging from 0 (impossible) to 1 (certain).
Step-by-step explanation:
An event in probability is a term that describes any combination of outcomes from a given experiment. In mathematical terms, an event is a subset of the sample space, which is denoted by an uppercase 'S'. The sample space represents all possible outcomes. When an event is defined, it is often represented by uppercase letters like 'A' or 'B'. For instance, if the experiment involves flipping three coins, event A could be defined as the occurrence of getting at most one head among the three flips.
The probability of an event, denoted as P(A), indicates how likely it is for that event to occur, with a value ranging between 0 and 1. A probability of 0, written as P(A) = 0, signifies that event A is impossible and cannot happen. Conversely, a probability of 1, or P(A) = 1, means that event A is certain to happen every time the experiment is conducted. A probability of 0.5, or P(A) = 0.5, suggests that event A has an equal likelihood of occurring or not occurring.