four features          MAE  121.5  RMSE  153.2  R2 0.9818
  dist  0- 3 km: mean residual   210.3  (28 houses)
  dist  3- 6 km: mean residual    23.5  (37 houses)
  dist  6-10 km: mean residual  -147.9  (53 houses)
  dist 10-15 km: mean residual   -63.4  (71 houses)
  dist 15-21 km: mean residual   109.4  (51 houses)
plus dist_km squared   MAE  111.6  RMSE  146.7  R2 0.9834
