I am absolutely new to GIS.
I have imported a map with information in the counties of Germany. Additionally I have added a layer with information on SO2 concentration at various measuring stations in Germany:
Additionally, I have already interpolated the SO2 data using IDW (based on the suggestions from the Federal Environmental Agency, who distributed the data):
I am now struggeling with calculating area means. That is, for my analysis I need one value of SO2 concentration for each county in Germany, which I can export to R.