AP Statistics Chapter 5 Vocabulary (Probability)

Random

Individual outcomes are uncertain, but there is a regular distribution in large repetitions.

Law of Large Numbers

Proportion of times an outcome occurs approaches a single value as repetitions increase.

Probability

A number between 0 and 1 describing long-term outcome proportions of a chance process.

Simulation

The imitation of chance behavior based on a model that accurately reflects it.

Sample Space (S)

The set of all possible outcomes of a chance process.

Event

Any outcome or set of outcomes of a random phenomenon; a subset of S.

Probability Model

Description of a chance process consisting of sample space and probabilities for outcomes.

Tree Diagram

A diagram that helps organize possible outcomes of a multi-stage process.

Multiplication Principle

Determines total outcomes by multiplying the number of choices at each stage.

Complement

Given event A, the complement Aᶜ is the event that A does not occur.

Complement Rule

The probability that an event does not occur is 1 minus P(A): P(Aᶜ) = 1 - P(A).

Mutually Exclusive (Disjoint)

Two events that have no outcomes in common.

Union

All outcomes in event A or event B or both. Symbol: A ∪ B.

Intersection

All outcomes common to both events A and B. Symbol: A ∩ B.

General Addition Rule

P(A ∪ B) = P(A) + P(B) - P(A ∩ B).

Independent Events

Knowing one event occurs does not change the probability that the other occurs.

Venn Diagram

A diagram that visually shows the sample space of joint and disjoint events.

Conditional Probability

The probability that one event happens given that another event has already occurred.