Represent the data by a stem-and-leaf plot, a histogram, and a boxplot:

Foundrax test of Brinell hardness (2.5 mm steel ball, 62.5 kg load, 30 sec) of 20 copper plates (values in kg/mm²)

86     86     87     89     76     85     82     86     87     85

90    88    89    90    88    80    84    89    90    89