Discrete random variance
The variance is, in short, a measure of how much the values of a random variable differ from the mean. It’s the square of the standard deviation.
Notation
Section titled “Notation”We write the variance of a list of values
Formula
Section titled “Formula”Suppose we have a list of possible discrete values and their probabilities.
The value at position
The variance of the list is calculated by:
We can substitute the formula for expectation into this -