Per capita crime rate by town
Proportion of residential land zoned for lots over 25.000 sq.ft.
Proportion of non-retail business acres per town
Charles River dummy variable (=1 if tract bounds to river; 0 otherwise)
Nitric oxides concentration squared (parts per 10 million)
Average number of rooms per dwelling
Proportion of owner-occupied units built prior to 1940
Weighted distances to five Boston employment centers
Index of accessibility to radial highways
Full-value property-tax per USD 10,000
Pupil-teacher ratio by town
1000(Bk-0.63)^2 where Bk is the proportion of blacks by town
Percentage of lower status of the population