# A First Course to Network Coding/Probability: Concepts and Useful Equations

## Random VariableEdit

In probability and statistics, a **random variable**, **aleatory variable** or **stochastic variable** is a variable whose value is subject to variations due to chance (i.e. randomness, in a mathematical sense).

## Mutual IndependenceEdit

In probability theory, to say that two events are independent means that the occurrence of one does not affect the probability of the other. Similarly, two random variables are independent if the realization of one does not affect the probability distribution of the other.

## I.I.DEdit

In w:probability theory and w:statistics, a w:sequence or other collection of random variables is **independent and identically distributed** (**i.i.d.**) if each random variable has the same w:probability distribution as the others and all are mutually independent.