Symbols:V

Roman Numerals

 * $\mathrm V$ or $\mathrm v$

The Roman numeral for $5$.

Variance

 * $\operatorname{var} \left({X}\right)$

Let $X$ be a discrete random variable.

Then the variance of $X$, written $\operatorname{var} \left({X}\right)$, is a measure of how much the values of $X$ varies from the expectation $E \left({X}\right)$, and is defined as: