How to add trend lines to your scatter plot
In the Scatter template, you can enable a trend line to better showcase the pattern of your plotted points.
NOTE: Please note that trend lines only work with numerical data. If one of your axes displays categorical information, such as dates or labels, they won't display.
The One per discrete color (grid of charts) option displays all trend lines in every grid – useful when you want to compare them all together in greater detail.