Skewness measures distribution asymmetry. Skewness = Σ(xi - x̄)³/(nσ³). Interpretation: Skew = 0 (symmetric); > 0 (right-skewed, tail right); < 0 (left-skewed, tail left). Relationship: Right-skew → mean > median > mode. Left-skew → mean < median < mode. Symmetric → mean = median = mode. Coefficient: Pearson's skewness = 3(mean - median)/σ. Example: Salaries. Mean = 60K, Median = 50K, σ = 15K. Skewness = 3(60-50)/15 = 2 (right-skewed). Exam tip: Identify distribution shape from skewness value. Understand relationship with mean/median/mode. Practice: Calculate and interpret for various datasets.