Box Plots

Two classes both have a median test score of 75. By that single number they look identical. But Class A's scores all sit between 70 and 80 — tight and consistent. Class B's range from 42 to 98 — wild and uneven. The median hid everything that mattered. To see the spread at a glance, you need a picture built from five numbers: the minimum, the first quarter, the middle, the third quarter, and the maximum. That picture is the box plot.