May 2022
Beginner to intermediate
448 pages
13h 7m
Korean
book
밑바닥부터 시작하는 데이터 과학 데이터 분석을 위한 파이썬 프로그래밍과 수학·통계 기초
by Joel Grus, Hangyeol Kim, Seongju Ha, Eunjung Park
Content preview from 밑바닥부터 시작하는 데이터 과학 데이터 분석을 위한 파이썬 프로그래밍과 수학·통계 기초
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from Scratch
75
식을 살펴보면 편차의 제곱의 평균을 계산하는 데,
n
대신에
n-1
로 나누는 것을 확인할 수
있다. 이는 편차의 제곱 합을
n
으로 나누면 편향(bias) 때문에 모분산에 대한 추정값이 실
제 모분산보다 작게 계산되는 것을 보정하기 위해서다.
3
데이터 포인트의 단위(우리의 경우 ‘친구 수’)가 무엇이든 간에 중심 경향성은 같
은 단위를 가진다. 범위(
range
) 또한 동일한 단위다. 하지만 분산의 단위는 기존
단위의 제곱이다(즉, ‘친구 수의 제곱’). 그렇기 때문에 분산 대신 원래 단위와 같
은 단위를 가지는
표준편차(
standard
deviation
)를 이용할 때가 많다.
import math
def standard
_
deviation(xs: List[float]) -> float:
"""
표준편차는
분산의
제곱근
"""
return math.sqrt(variance(xs))
assert 9.02 < standard
_
deviation(num
_
friends) < 9.04
범위와 표준편차 또한 평균처럼 이상치에 민감하게 반응하는 문제가 있다. 이전
예시와 동일하게, 친구 수가 가장 많은 사용자에게
200
명의 친구가 있다면 표준
편차는
60
%나 증가한
14
.
89
가 된다!
더 안정적인 방법은 상위
25
%에 해당되는 값과 하위 ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.