26.5     31.2     27.9     30.8
28.7     28.3     25.1     29.6
25.1     30.8     28.5     32.4
29.1     27.9     24.2     31.7
27.2     29.6     26.5     32.8

none     pink     orange   green     (color of drink)
Response: cases sold per 1000 population.

Opgave 9.5.1, Statistik side 93.

Neter, Wasserman and Whitmore: Applied Statistics.