I have a list in which I now-and-then (no fixed interval) enter the available budget.
Most of all I want to extrapolate this to a future trend of the coming 10 years. (no rocket science, more of an average through line of the last 4-5 samples, as you would have in stock market charts or so)
Possible as an inbetween step I would like to aggregate this to one average number per quarter. As in most quarters there is no data available, it should mean interpolation. (or interpolation for all: so regarding Jan/April/Juli/Oct 1st. If it is always interpolated between the nearest neighbours... fine with me.)
I am familiar with the common aggregate functions, but I have no idea, what to use on such irregular entered data. I have seen some stuff on extrapolation, but that was monstly on sequences (not x⤇y).
Thank you for your help :)