I’m a great believer in solving hard problems by using a checklist. You need to get all the likely and unlikely answers before you； otherwise it’s easy to miss something important.
我非常相信用清单来解决难题。你需要在你面前得到所有可能和不可能的答案；否则很容易错过一些重要的东西。
I think that plays are there to disturb, not to reassure.
从n对观测值的样本中获得的相关系数的可能误差是sqrt((1-r²)/(n-2))。