# Stats: 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.

Table of Contents