1. Starting from 0, random sample a number from 0-1, what is the expected number of samples to reach a sum over 2?
2. Given a group of data pair {x,y}, the mean and correlation at x>0,y>0 , x>0,y<0, x<0,y<0, x<0,y>0 are provided, find a way to check if the are linear correlated
