- Line<span> of </span>Best Fit<span>. A </span>line<span> of </span>best fit<span> (or "</span>trend<span>" </span>line<span>) is a straight </span>line<span> that </span>best<span> represents the data on a </span>scatter plot<span>. This </span>line<span> may pass through some of the points, none of the points, or all of the points.</span>