Measures of Spread (VCE SSCE Mathematical Methods): Quizzes

How far values typically fall from mean

$\sigma^2$

Square metres

$\text{sd}(X) = \sqrt{\text{Var}(X)}$

$\sigma$

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

Variance and standard deviation

Middle 50%

$\text{IQR} = Q_3 - Q_1$

Not affected by extreme values in tails