What you’ll learn
Read and create box plots.
Key idea
Use the stated median-of-halves quartile convention; even-sized halves require their middle-pair average.
Whiskers mark extremes, box edges quartiles and the internal line the median; even halves require averaging their middle pair.
Worked example
Enter the exact value or ordered values in the format requested below.
Read this labeled box plot: left whisker 2; left box edge 14; median line 30; right box edge 46; right whisker 58. Enter exact Q3.
- Using median-of-halves, Q1=14, median=30, Q3=46; extrema are 2 and 58.
- The box runs from 14 to 46, so its central interval width is 32; whiskers mark the overall extrema.
Answer: 46
Quick Check
Relate the graph used in 'Read and create box plots' to an equation, table, transformation, or verbal description.
A box plot's landmarks are min=6,Q1=15/2,median=19/2,Q3=23/2,max=13. Connect the central box to its data interpretation.