We use the Boston data in the MASS package. This data was collected by urban planners to generate quantitative estimates of the cost-benefit for improving air quality. The response variable of interest ‘medv’ is the median value of owner-occupied homes. The Boston data.frame has dimensions 506, 14. The variables are described in Table 1.
| Variable.. | …Description | |
|---|---|---|
| 1… | crim | per capita crime rate by town |
| 2… | zn | proportion of residential land zoned for lots over 25,000 sq.ft |
| 3… | indus | proportion of non-retail business acres per town |
| 4… | chas | Charles River dummy variable (= 1 if tract bounds river; 0 otherwise) |
| 5… | nox | nitrogen oxides concentration (parts per 10 million) |
| 6… | rm | average number of rooms per dwelling |
| 7… | age | proportion of owner-occupied units built prior to 1940 |
| 8… | dis | weighted mean of distances to five Boston employment centres |
| 9… | rad | index of accessibility to radial highways |
| 10… | tax | full-value property-tax rate per $10,000 |
| 11… | ptratio | pupil-teacher ratio by town |
| 12… | black | 1000(Bk - 0.63)^2 where Bk is the proportion of blacks by town |
| 13… | lstat | lower status of the population (percent) |
| 14… | medv | median value of owner-occupied homes in $1000s |