out why this happens namely because the data set is mainly Caucasian people so the results of up sampling are going to be mainly Caucasian people I mean this is like a straightforward explanation of why we're seeing what we're seeing but of course this was not okay and here is where the piling starts as an interjection we have to talk about bias in machine learning technically there is a statistical notion of bias which has a very rigorous definition and there is the societal definition of bias and these two things even though they're the