Complementary Events

The events of one outcome happening and that outcome not happening. The sum of the probabilities of an event and its complement is 1 or 100%. In symbols, P(A) + P(not A) = 1.

Compound Event

An even consisting of two or more simple events.

Dependent Events

Two or more events in which the outcome of one event affects the outcome of the other event(s).

Experimental Probability

An estimated probability based on the relative frequency of positive outcomes occurring during an experiment. It is based on what actually occurred during such an experiment.

Fair [Game]

A game where each player has an equally likely chance of winning.

Fundamental Counting Principle

Uses multiplication of the number of ways each event in an experiment can occur to find the number of possible outcomes in a sample space.

Independent Events

Two or more events in which the outcome of one even does not affect the outcome of the other event(s).

Outcome

Any one of the possible results of an action. For example, 4 is an outcome when a number cube is rolled.

Permutation

An arrangement, or listing, of objects in which order is important.

Probability

The chance that some event will happen. It is the ration of the number of favorable outcomes to the number of possible outcomes.

Random

Outcomes occur at random if each outcome occurs by chance. For example, rolling a number on a number cube occurs at random.

Relative Frequency

A ratio that compares the frequency of each category to the total.

Sample Space

The set of all possible outcomes of a probability experiment.

Simple Event

One outcome or a collection of outcomes.

Simulation

A mathematical experiment that approximates a real-world process.

Theoretical Probability

The ration of the number of ways an event can occur to the number of possible outcomes. It is based on what should happen when conducting a probability experiment.

Tree Diagram

A diagram used to show the sample space.

Uniform Probability Model

A probability model which assigns equal probability to all outcomes.

Unfair [Game]

A game where there is not a chance of each player being equally likely to win.