Finding the best-fit line
| Oct | Nov | Dec | Jan | Feb | Mar | Apr | May | June | |
| Degree-days per day | 15.6 | 26.8 | 37.8 | 36.4 | 35.5 | 18.6 | 15.3 | 7.9 | 0.0 |
| Gas consumed per day (100 cubic feet) | 5.2 | 6.1 | 8.7 | 8.5 | 8.8 | 4.9 | 4.5 | 2.5 | 1.1 |
(a) A scatter plot of the data
(b) A linear-regression line
| Computing the best-fit line |
How useful is the best-fit line?
Some data sets are more linear than others. Correlation measures this relationship.
(See p. 35 of your textbook for the formula.)
What if the data is nonlinear?
| Data can fit to other types of equations. |
 |