Appendix H: Adding A Trendline to a Graph
As you might know, it is easy to create a chart of existing data using Excel. It is equally easy to add a trendline (line of best fit) to your data and display the equation to the trendline in Excel. From the equation to the trendline the slope and intercept can be determined.1
To add a trendline, right click one of the points of the graph and select Add Trendline from the pop-up menu. Alternately, click on 'chart' in the tool bar on top and select Add Trendline.
2
Click the options tab if it is not already selected.
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Select Display equation on chart.
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In some cases you will be asked to force the y-intercept to pass through zero. To do this, select the Set Intercept = field and type 0 in the box.
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Once you make your selections, click OK.
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The graph will display a line that best fits your data along with the equation to the trendline as shown in Fig.1 below.
Figure 1: Adding an equation and trendline