### 12.1 Linear Equations

*y* = *a* + *bx*, where *a* is the *y*-intercept and *b* is the slope. The variable *x* is the independent variable and *y* is the dependent variable.

### 12.4 Testing the Significance of the Correlation Coefficient (Optional)

Least-Squares Line or Line of Best Fit:

$\u0177=a+bx\text{,}$

where *a* is the *y*-intercept and *b* is the slope.

Standard Deviation of the Residuals:

$s=\sqrt{\frac{\text{SSE}}{n-2}},$

where SSE = sum of squared errors, and

*n* = the number of data points.