Below is a scatter plot of the 20 counties comparing rates
of off-sale alcohol outlets (on the bottom) with rates of
underage drinking arrests (on the left). Underage drinking
arrests include juvenile arrests for DUI, public drunkenness,
and violation of liquor laws. Mendocino County is
denoted by the triangle. Using linear regression analysis on
this data and applying the resulting equation, a practical
finding is that each additional off-sale alcohol outlet is associated
with almost 3 more arrests for underage drinking.
The number of outlets accounted for 20% of the variation
in underage drinking arrests.