Note: Trendlines are available only for certain chart types (including two-dimensional column, bar, and line charts). Other limitation: They are not available for stacked chart types.
If desired, you can add trendlines to the data series of a chart.
Trendlines can be used to graphically display the trend of a data series (i.e., to what extent the data series rises/falls on average). Trendlines can also be extended beyond the given data points, so that they display a forecast for future values.
A statistical technique called regression analysis is used to calculate trendlines.
To show/hide trendlines, proceed as follows:
Via the "Add chart element" icon
Select the desired data series to which you want to add a trendline.
Use the ribbon command Chart | Add chart element 
to choose the entry Add trendline. In the following submenu, select one of the predefined trendline types.
The entry Remove all removes all trendlines. (Select the chart for this purpose.) To remove individual trendlines, select the desired trendline and then choose Remove all or simply press the Del key.
The entry More takes you to the dialog box with additional options (see below).
Via the dialog box
You will find more trendline types and additional options via the dialog box:
| 1. | Select the chart by clicking on it. |
| 2. | Use the ribbon command Chart | Add chart element to choose the entry Add trendline and select More in the following submenu to open the dialog box. |
| Alternatively: Select the desired data series and right-click to open the context menu and select the entry Add trendline. |
| 3. | Switch to the Trend tab and enable the desired settings. |
For more information on the options of the dialog box, see Trendlines.