experiment: possible outcomes, probability of outcome random variable: possible values, probability of value Tables, e.g. for dice:
| x | P(X = x) |
|---|---|
| 1 | $\frac{1}{6}$ |
| 2 | $\frac{1}{6}$ |
| 3 | $\frac{1}{6}$ |
| 4 | $\frac{1}{6}$ |
| 5 | $\frac{1}{6}$ |
| 6 | $\frac{1}{6}$ |
E(X): sum of (x times its probability)
$Var(X) = \sum_{i}^{k} \lbrack x_{i}^{2} P(X = x_{i}) \rbrack - \mu^{2}$
in english: to get variance, sum the (square of each value times its probability) and subtract the square of the mean.