L4 Line of Best Fit
Completion requirements
Unit D: Graphing
Line of Best Fit
The line of best fit (or "trend" line) is a straight line that best represents the data on a scatterplot. This line can show positive correlation or negative correlation. The line may pass through some of the points, none of the points, or all of the points. To draw the line of best fit, draw the line as close as possible to all points on the scatterplot. The line is drawn so that there are approximately the same number of points above the line as there are below the line. The line of best fit must be drawn with a straight edge.
Positive correlation graph
Positive correlation graph with line of best fit
Sometimes when graphing a scatterplot, all the points seem to follow the trend line except for one or two points. These points are called outliers. When drawing the line of best fit, ignore outliers if only one or two points do not follow the trend.
Negative correlation graph
Negative correlation graph with line of best fit
The outlier is not considered when drawing the line.