L12.2 The Sum of Independent Discrete Random Variables
https://youtu.be/zbu8KQx9bqM
L12.3 The Sum of Independent Continuous Random Variables
https://youtu.be/d2M4LNSeIn4
L12.4 The Sum of Independent Normal Random Variables
https://youtu.be/aGbP_7yAiEk
covariance 와 correlation Coefficient에 대해 쉽게 설명한 한국어 블로그 링크
https://m.blog.naver.com/PostView.nhn?blogId=sw4r&logNo=221025662499&proxyReferer=https%3A%2F%2Fwww.google.com%2F
L12.5 Covariance
https://youtu.be/K2Tlj27nkjs
L12.6 Covariance Properties
https://youtu.be/RQKJBpaCCeo
L12.7 The Variance of the Sum of Random Variables
https://youtu.be/GH7dwoXSD0s
L12.8 The Correlation Coefficient
https://youtu.be/HTs6Zhc2S1M
L12.9 Proof of Key Properties of the Correlation Coefficient
