Regression Function

The equation of the least square fit line through the data, used to estimate values of the dependent variable (the Y axis) for given values of the independent variable (the X axis).

Note: Caution should be exercised in extrapolating the regression line beyond the region of the data.

$images\conc0073_wmf.jpg$

Where β1 (the slope) and β0 (the intercept) are calculated as follows:

$images\conc0074_wmf.jpg$

$images\conc0075_wmf.jpg$

$images\conc0076_wmf.jpg$

$images\conc0077_wmf.jpg$

where N is the total number of observations, x-doublebar and y-doublebar are the Averages of x and y, respectively, and σx is the Sample Sigma of x.