Probability Distributions

Definitions

Random Variable
Variable whose values are determined by chance
Probability Distribution
The values a random variable can assume and the corresponding probabilities of each.
Expected Value
The theoretical mean of the variable.
Binomial Experiment
An experiment with a fixed number of independent trials. Each trial can only have two outcomes, or outcomes which can be reduced to two outcomes. The probability of each outcome must remain constant from trial to trial.
Binomial Distribution
The outcomes of a binomial experiment with their corresponding probabilities.
Multinomial Distribution
A probability distribution resulting from an experiment with a fixed number of independent trials. Each trial has two or more mutually exclusive outcomes. The probability of each outcome must remain constant from trial to trial.
Poisson Distribution
A probability distribution used when a density of items is distributed over a period of time. The sample size needs to be large and the probability of success to be small.
Hypergeometric Distribution
A probability distribution of a variable with two outcomes when sampling is done without replacement.