Which of the following represents an event in probability?

In probability, an event is defined as a collection of outcomes from a random experiment that are of interest to the observer. This means that when we talk about an event, we refer to one or more outcomes that we want to analyze or consider. For instance, if we are rolling a die, an event might be rolling an even number, which includes the outcomes 2, 4, and 6.

The options that do not accurately represent an event include the other choices. An outcome that does not occur refers to a single or non-event situation, while the total number of outcomes relates to the sample space rather than events. The calculation of variance is a statistical measure that quantifies the spread of a set of data points but does not pertain to the definition of an event in probability. Thus, recognizing that an event is fundamentally a collection of outcomes is key to understanding probability concepts.