An 1854 study on mental health in the fourteen counties of Massachusetts yields data on 14 cases. This study was performed by Edward Jarvis (then president of the American Statistical Association)
The variables included in the dataset are:
NBR
the number of "lunatics" per county.
DISt
distance to the nearest mental healthcare center
POP
population in the county by thousands
PDEN
population per square county mile
PHOME
the percent of "lunatics" cared for in the home
data(lunatics)