Event

Definition

An event is a set of outcomes of an experiment to which a probability is assigned. It is a subset of the sample space.

5 Must Know Facts For Your Next Test

1. The probability of an event $A$ occurring is denoted by $P(A)$ and ranges from 0 to 1.
2. An event that contains all possible outcomes of an experiment is called a certain event, and its probability is 1.
3. An impossible event has no outcomes and its probability is 0.
4. Two events are mutually exclusive if they cannot occur at the same time, meaning $P(A \cap B) = 0$.
5. The complement of an event $A$, denoted by $A'$, consists of all outcomes in the sample space that are not in $A$, and $P(A') = 1 - P(A)$.

Review Questions

• What is the probability range for any given event?
• Define a mutually exclusive event.
• How do you calculate the probability of the complement of an event?

Related terms

Sample Space: The set of all possible outcomes in a probabilistic experiment.

Mutually Exclusive Events: Two events that cannot happen at the same time. If one occurs, the other cannot.

Complementary Events: $A'$ represents the set of all outcomes not in event $A$. The probabilities sum to one: $P(A) + P(A') = 1$.