After creating a chart in Microsoft Excel, a best fit line can be found as follows:
1. Be sure you are on the worksheet which contains the chart you wish to work with.
2. Move the mouse cursor to any data point and press the left mouse button. All of the data points should now be highlighted. Now, while the mouse cursor is still on any one of the highlighted data points, press the right mouse button, and click on Add Trendline from the menu that appears.
3. From within the "Trendline" window, click on the box with the type of fit you want (e.g., Linear).
4. Click on Options at the top of the "Trendline" window.
5. Click in the checkbox next to "Display Equation on Chart" and the checkbox next to "Display R-squared Value on Chart". Do not click on the checkbox next to "Set Intercept = 0".
6. Click OK. A line, an equation, and an R-squared value should appear on the graph as shown in figure 6 below.
Figure 6: Plot of Data Including Trendline, Equation of Line, and R-Squared Value