What is an Event (Probability Theory)?
In probability theory, an event is a set of outcomes of an experiment to which a probability is assigned. For example, when you roll a dice there are usually 6 possible outcomes, either a 1, 2, 3, 4, 5, or 6 will be rolled. When you roll the dice and observe the number rolled, that is an event. The probability that any number will be rolled is ⅙. An event can be just one outcome or it can be a combination of more than one outcome from an experiment. There are simple events where only a single outcome of the experiment is considered the event. Some experiments only allow for simple events because they cannot be broken down any further. There are also compound events where two or more simple events are combined. A compound event can also be an event that has two or more sample points.
For Example, in an experiment you roll two dice simultaneously. If the event consist of the sum of the two dice is 5 then it consists of the following four possible outcomes: (1,4), (2,3), (3,2), (4,1). This is considered to be a compound event.
Why is this Useful?
An event is a basic part of probability theory, and it is necessary to understand probability and statistics. Probability is the science of how likely events are to happen. There are very simple applications of probability, such as rolling a dice or tossing a coin. There are also advanced concepts that help us understand complex science and make important life decisions.