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Theoretical Probability

Probability based upon what should happen.

Experimental Probability

Probability based upon data collected.

Odds in Favor

The ratio of the favorable outcomes to the unfavorable outcomes.

Odds Against

The ratio of the unfavorable outcomes to the favorable outcomes.

Population

Any group of objects or people in a survey.

Sample

Is a part of the population.

Random Sample

Each object or person in the population has the same chance of being selected.

Biased Questions

Unfair questions in a survey that may influence your response.

Independent Events

Events that do not influence each other (the occurrence of one does not affect the probability of the second.)

Dependent Events

Events that influence on another (the occurrence of one affects the probability of the second.)

Permutation

An arrangement of a set of items in a particular order.

Factorial

The product of all positive integers less than or equal to a number (uses the "!" symbol.)

Combination

A group of items in which the order of the items is not considered.