October 2014
Intermediate to advanced
288 pages
6h 27m
Japanese
Content preview from 実践 機械学習システム
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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.
5.7
適合率と再現率
105
図5-10
5.7
適合率と再現率
私たちはこれまでずっと分類器の評価を行うために正解率という指標を用いてきました。ここでは
今一度、私たちが達成したいことについて考えることにします。実際、私たちは回答の良し悪しを完
璧に予測できる分類器を求めていません。
もし、どちらか一つのクラスだけは上手く予測できるように分類器を調整することができたら、それ
に応じてユーザへ適切なフィードバックを与えることができるでしょう。たとえば、「ある文書を“悪
い”回答と予測した場合は、常に事実は正しい（実際に“悪い”回答である）」という能力のある分類
器があったとします。そのような場合、その分類器が回答を「悪い」と予測した場合にのみ、私たちは
ユーザにフィードバックを与えるでしょう。これとは逆に、「ある文書を“良い”回答と予測した場合
は、常に事実は正しい」という分類器の場合、初めはユーザに役立つコメントを表示しておいて、分類
器が回答を
「良い」と予測した段階で、そのコメントを表示しないようにすることができます。
私たちの置かれている状況をより良く理解するためには、適合率（precision）と再現率（recall）に
ついて理解する必要があります。そのために、表5-6に示される4つの分類結果（予測と事実の組み合
わせ）について見ていきたいと思います。
LogReg C=0.10におけるバイアス－バリアンス
データサイズ
テスト誤差
訓練誤差
106
5
章 クラス分類：悪い回答を判別する
表5-6
たとえば、
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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.