Related Definitions
Random variable: It is not a variable in the traditional sense of the world. It is actually a function. The outcome of an experiment need not be a number, for example, the outcome when a coin is tossed can be 'heads' or 'tails'. However, we often want to represent outcomes as numbers [STEPS]. A random variable is a function that associates a unique numerical value with every outcome of an experiment. Random variable is written as capital letter, usually X.
Probability distribution and probability density are similar, where distribution is used for discrete variable and density is used for continuous variable.
Expected Value: The expected value (or population mean) of a random variable indicates its average or central value. It is a useful summary value (a number) of the variable's distribution [STEPS].
The expected value of a random variable X is symbolised by E(X) or ยต.
If X is a discrete random variable with possible values x1, x2, x3, ..., xn, and p(xi) denotes P(X = xi), then the expected value of X is defined by:
where the elements are summed over all values of the random variable X.