ABSTRACT
An event is a particular outcome of a trial, test, experiment, or process. It is a particular category for the outcome. The outcome category could be dichotomous, meaning either one thing or another. By contrast, the outcome may be a continuum-valued variable, such as temperature, and the event might be defined as sampling a temperature with a value above 85 degree Fahrenheit. The value of the event probability can be either derived from fundamental principles, representing an infinite number of experiments, or calculated from a finite number of experiments. Two types of probabilities are of primary interest to engineers. The first is a priori probability, in which the people assume that the composite/compound event will happen and that its probability can be predicted or calculated prior to the experiment. The second is a posteriori, or conditional, probability, which is calculated after some evidence is obtained. .
