Variance of a Discrete Random Variable

The variance is calculated as $\sigma^2 = \sum x^2 \cdot p(x)$ without subtracting the mean.

The variance is calculated as $\sigma^2 = \Big(\sum x \cdot p(x)\Big)^2$.

The variance is calculated as $\sigma^2 = \sum (x - \mu)^2 \cdot p(x)$, summing over all outcomes.

The variance is calculated as $\sigma^2 = \sum (x - \mu) \cdot p(x)$.