A regression line is a line drawn through the points on a scatter or bubble chart to summarize the relationship between the variables being studied. Also called a trendline, a regression line is a graphical representation of trends in the group, often used for the study of problems of prediction. The slope represents the degree to which the variables are related. When it slopes down (from top left to bottom right), this indicates a negative or inverse relationship between the variables; when it slopes up (from bottom right to top left), a positive or direct relationship is indicated.
1.Click on Series from the Edit Chart toolbar
2.This brings up the Format Series Task Pane
3.In the Data Set Groups tab, indicate for which group you wish to draw your regression line.
5.Select the number format (including percent, number of decimal places, and units or currency if applicable) for the regression line. You can also designate which series you wish to display regression, choose the color, line style, and weight of the regression lines.
TOTAL REGRESSION LINE
You can also draw a total regression line where the regression line will include all data sets in the regression. To draw a total regression line, go to the Format Series Task Pane and in the Data Set Groups section, at the bottom, check the box for Total Regression Line.
Note: Bubble charts should have the Group field populated in the datasheet in order to draw a regression line.