Surpassing Human Level Performance

Dear Mentor,

Here in the below slide from Surpassing human level performance lecture video, we are having doubts. can you please clarify,

1.Training error is 3% and it surpasses team of humans 0.5% then it make sense harder to tease out bias but we can reduce to reduce variance 0.1% error right. why professor andrew not talking about it … because only the bias tactics are harder to apply right.

Sorry, I do not completely understand your question.