calculate weighed Fst value based on sliding window Fst calculations

Question

[Cecelia]

I have a list of Fst calculations (Weir & Cockerham'S Fst Estimator) based on sliding window (window size 20k, window step 10k) that looks like this:

> scaffold  start   end sites   Fst 
> scaffold1 10001   20000   522 0.3793
> scaffold1 20001   30000   744 0.3666 
> scaffold1 30001   40000   260 0.3221
> scaffold2 10001   20000   124 0.0123 
> scaffold2 20001   30000   322 0.0185
> scaffold3 10001   20000   223 0.0222

I had a hard time understanding how to calculate the weighed Fst based on the sliding window counts. Any help will be much appreciated.