First, calculate the linear regression factors: y=ax+b with the following formula:
Then add another column next to the y-axis and name it calculated y-axis. Build the following formula to calc. the y-axis and copy that for all x-values.:
Next is a piece of cake. Add the calculated y-axis to the existing data range or ...
Use the SMA (Simple moving average). It works as follow
Take W points back (e.g. 3, 5 or 10, that's your window size) and do an average for them. This will create a new point
Use those newly created points to plot your line.
NOTE: at the end you'll have N-W+1 points where N is original number of points and W is your window size
Here is an example google ...
There's multiples ways to do this :
I used =Trend but =Growth works too.
=Forecast is an amazing function too.
You can use Arrayformula for extra lazyness :
Theses formulas will be accurate the more data you feed them.
I updated ...