August 2015
Intermediate to advanced
272 pages
5h 46m
Japanese
Content preview from Think Stats 第2版 ―プログラマのための統計入門
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114
8 章 推定
•
標準誤差と標準偏差を取り違える人がいる。標準偏差は、測った量の変動を
記述するのだということを覚えてほしい。この例では、ゴリラの体重の標準
偏差は
7.5 kg
である。標準誤差は、推定における変動を記述する。この例では、
9
頭の標本の測定に基づく平均の標準誤差は
2.5 kg
である。
違いを覚える方法の
1
つは、標本サイズが増えたときに、標準誤差は小さく
なり、標準偏差はそうならないことを理解することだ。
•
実パラメータμが
90
％信頼区間にあるということが、
90 %
の確率でそうな
ると思っている人がいる。残念ながらそれは間違いだ。そのようなことを述
べたいなら、ベイズ手法を使う必要がある（拙著、『
Think Bayes
̶̶
プロ
グラマのためのベイズ統計入門』を読んでほしい）。
•
標本分布は別の質問にも答える。すなわち、さらに実験を繰り返せば推定値
がどれほど変動するかを示すことで、推定値がどれだけ信頼できるかという
印象を与える。
信頼区間と標準誤差とが標本誤差を定量化しているだけだということを覚えておく
のが重要です。すなわち、母集団の一部しか測定しないことに起因する誤差なのです。
標本分布には、他の誤差の原因は直接関係しません。そのような原因で有名なのは標
本バイアスや測定誤差で、次節の主題です。
8.4
標本バイアス
自然公園でのゴリラの体重ではなくて、住んでいる町の女性の平均体重を知りたい
と仮定しましょう。女性の代表的標本を選んで体重を量る許可をもらうのは難しいで
しょう。
簡単な代案は、 ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
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.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
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.