Setting Up Trend Line

A trend line enables the user to display tendencies in the visual form. Such type of analysis is named regression analysis. Regression analysis can be used to extend the trend line in a bubble chart beyond the borders of actual data to predict future values.

By default, a trend line is not displayed. To set up visibility and parameters of tooltips, select the checkbox in the title of the Trend Line tab on the side panel.

Make sure that the side panel is displayed.
Select a bubble chart in the working area.
Select the Format radio button on the side panel and go to the Trend Line tab.

After the Trend Line checkbox is selected, the following settings are available:

Select trend line type in the Type drop-down list:

Linear. It is applied in simple cases when data series points are located close to the trend line. The linear type of trend line is applicable to the value that increases or decreases at a constant speed.
Power. The power type of trend line shows good results if the dependency contained in data increases at a constant speed. The example of such dependency may be race car acceleration at each time interval equal to one second. If there are zero or negative value in the data, power trend line type cannot be used.
Exponential. The exponential trend line is a curve that should be used if data change speed increases constantly. However, for the data that contain zero or negative values, this trend line type cannot be used.
Logarithmic. The logarithmic trend line describes well the value that increases or decreases fast at the beginning and then gradually stabilizes. The logarithmic trend line can be used both for negative and positive data values.
Mean. The trend line that passes through the data series mean. Such trend line enables the user to track the dynamic of changing the value in question depending on the mean.

The trend line is the most accurate when determination coefficient value (r2) is close to one.

If required, set up trend line parameters: color, type and line width.

To display trend line icon and name in a bubble chart legend, select the Show in Legend checkbox.

After the checkbox is selected, additional parameters of trend line become available:

With a Different Name. If the checkbox is selected, the legend element that corresponds to trend can be renamed. By default, the name contains trend type. For example: Linear trend.