July 2014
Beginner to intermediate
456 pages
11h 26m
Japanese
Content preview from 戦略的データサイエンス入門 ―ビジネスに活かすコンセプトとテクニック
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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.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.
58
3 章 予測モデリング：相関から教師ありセグメンテーションへ
のモデリング方法についても掘り下げて説明していきますが、その中には直接的には変数を
選び出さない方法もあります。そのような方法を使う場合でも、もし属性の数が多すぎて困
るようなときには、ここでの考え方に立ち戻ると情報価値の高い属性を選び出すために役に
立つでしょう。そうすることで、大きすぎて扱いづらいデータセットのサイズを実質的に減
らすことができ、結果としてより精密なモデルを作ることができます。
3.2.1
情報価値の高い有用な属性を選び出す
大量のインスタンスがあるとき、どうすればインスタンスを効果的に分類分けできる属性
を選べるでしょうか。ここではまず目的変数が
2
種類（
2
クラス）のうちいずれかになる問
題を考え、その後でその考えを広げていきます。具体的に考えるために、図
3-2
に簡単なセ
グメンテーションの問題を示します。この例では分類の対象とする人が
12
人います。
2
種類
の頭（正方形と円）と、
2
種類の体（長方形と楕円）があります。
2
人の体は黒で、残りの
10
人は白です。
こういった属性で図中の人がどのような人であるか記述しています。それぞれの人の上に
あるラベルは、
Yes
または
No
のいずれかの値となる目的変数で、その人の（例えば）借り
ているローンが回収不能になるかどうかを示しています。これらの人々についてのデータ
を、次のように記述することにします。
属性
•
頭の形：正方形、円
•
体の形：長方形、楕円
•
体の色：黒、白
目的変数
•
回収不能： ...
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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.