Introduction to Statistical Learning in Python 2nd Ed

Python Code Reference: https://github.com/JWarmenhoven/ISLR-python/tree/master

MSE of an estimation:

1. 1st term: when f(x) is repeatedly trained with different sets of training samples, how diff are the f’s
2. 2nd term: estimation bias, diff between f(x) and y
3. 3rd term: error from true value itself, which might have random components