| Average monthly temperature (in °F) | Observed monthly heating cost (in dollars) | Predicted monthly heating cost (in dollars) | Residual (in dollars) |
|-------------------------------------|--------------------------------------------|--------------------------------------------|-----------------------|
| 23.0                                | 51.00                                      | 63.94                                      | -12.94                |
| 35.7                                | 67.00                                      | 48.70                                      | 18.30                 |