Partition values (quartiles, deciles, percentiles) divide sorted data into equal parts. Quartiles Q₁, Q₂, Q₃ divide into 4 parts. Q₂ = median. Position of Qi = (i/4)(n+1). Deciles D₁...D₉ divide into 10 parts. Percentiles P₁...P₉₉ divide into 100 parts. For percentile Pk: Position = (k/100)(n+1), interpolate if needed. Five-number summary: Min, Q₁, Q₂, Q₃, Max. Interquartile range (IQR) = Q₃ - Q₁. Outliers: Values < Q₁ - 1.5×IQR or > Q₃ + 1.5×IQR. Example: Data {1, 3, 5, 7, 9, 11, 13}. Q₁ position = 2, Q₁ = 3. Q₃ position = 6, Q₃ = 11. IQR = 8. Exam tip: Calculate positions carefully. Use for data summary and outlier detection.