https://bkshin.tistory.com/entry/DATA-28-%EB%8B%A8%EB%B3%80%EB%9F%89-Univariate-%EB%8D%B0%EC%9D%B4%ED%84%B0-%EC%8B%9C%EA%B0%81%ED%99%94?category=1042793
