Discrete Probability Distributions (Edexcel A-Level Further Mathematics): Quizzes

A value that can take only certain fixed values

Its value depends on chance

List/formula of outcomes & probabilities

The actual outcome

$E(X) = \Sigma xp$

Mean score per turn

$E(X^2) = \Sigma x^2p$

$\text{Var}(X) = E(X^2) - [E(X)]^2$

$s^2$

$s^2 = \frac{n}{n-1}\sigma^2$