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
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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.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.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.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.
25
25
2.7 分布を要約する
ヒストグラムは、度数が見た目ですぐわかるので便利ですが、
2
つの分布の比較に
最適ではありません。この例では、「第一子」の方が「第二子以降」より人数が少な
いので、ヒストグラムで見た目の相違のいくつかは標本のサイズに起因するものです。
次章では、確率質量関数を使ってこの問題を扱います。
2.7
分布を要約する
ヒストグラムは標本の分布の完全な記述です。すなわち、ヒストグラムがあれば、
標本の値を（順序までは無理ですが）再構成できます。
分布の詳細が重要であれば、ヒストグラムを提示することが必要ですが、わずかな
記述統計量で分布を要約したいこともよくあります。
報告したい特徴のいくつかは次のようなものです。
•
中心傾向（
central tendency
）
値は特定の点の周りに集まっているか
?
•
最頻値（
modes
）
塊は複数あるか
?
•
散らばり（
spread
）
値の変動はどの程度か
?
•
裾（
tails
）
最頻値から離れると確率がどれぐらい下が
るか
?
•
外れ値（
outliers
）
最頻値から離れた極値があるか
?
これらの質問に答える統計量は、要約統計量（
summary statistics
）と呼ばれます。
一番良く使われる要約統計量は（算術）平均（
mean
）で、分布の中心傾向の記述と
して用いられます。
n
個の値の標本
x
i
が与えられれば、平均
-
x
は、値の和を値の個数で割ったものです。
すなわち、次のとおりです。
-
x
＝
1
−
n
Σ
i
x
i
普通の英語では、「
mean
」と「
average ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
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.