How to compute SD on a dataset based on results from both sub-partition result

1. https://en.wikipedia.org/wiki/Algorithms_for_calculating_variance#Two-pass_algorithm

see the part of parallel part.

2. https://stats.stackexchange.com/questions/43159/how-to-calculate-pooled-variance-of-two-groups-given-known-group-variances-mean

Tax Exemption under China-US Treaty

Follow this one to get more reduction on 5000 for each of the tax filing.


https://ttlc.intuit.com/questions/3220533-tax-exemption-under-china-us-treaty