Skewness
A measure of the asymmetry of a distribution. Calculated using the formula: skewness = (mean - mode) / standard deviation, or alternatively using (3(mean - median)) / standard deviation.
Real World
UK household income data from the ONS is positively skewed because most people earn moderate salaries, but a small number of Premier League footballers and CEOs pull the mean far above the median.
Exam Focus
State the direction of skew and justify using mean vs median comparison — simply saying 'skewed' without direction scores zero.
How well did you know this?