假设某一天，某媒体发布一条消息，说清华大学研究生新生录取的面试过程中，每个系的女性报考者的通过率都要比男性报考者的通过率要低，然后攻击清华大学的新生录取歧视女性。你对这件事情有何看法？

魔鬼经济学中教育我们要对数据进行分析，揭露隐藏在表象世界下的真实世界。但是，对于数据的不同分析方式，会得出截然不同的结果，至少表面上看起来截然不同。

比如在上面的例子，表面上看起来女性报考者在每个系都受到了歧视，但真实情况如何呢？

为了简单起见，不妨将各系分为两大类，文科系和理工科系，

表格里面的 a/b=c%的含义为b人报考，a人通过，通过率为c%。

这个例子便显示即使数据表明在每个系，女性通过率要低于男性，在全校范围看来，女性的通过率也可能比男性高，这样看来，歧视女性报考者的说法就无法成立了。

上面是一个例子，显示出数据必须从整体来看。下面是一个例子，单从整体来看数据也是不够的。

某气象台号称它的天气预报整体准确率高达80%。你对这个数据有何看法？

似乎80%是足够高了。但其实不然。大多数人关注的天气也就是下雨和不下雨之分。任何一个人都能预测天气，达到90%以上的准确率，只需要总是预测不下雨即可（显然，在北京，雨天的概率要<10%）。

想想看，你是否被人用上面的两种方法忽悠过？

注：上面的例子和数据均为作者伪造，清华大学也从没有歧视女性之说，请勿用作其它论据。

[tags]课堂笔记,TCS,数据分析,魔鬼经济学[/tags]

© zhiqiang for 阅微堂, 2007. | 链接 | 16 条评论

Tsinghua ITCS Theory Day (I)

time: Apr. 11, 2:00-5:00pm

The Institute for Theoretical Computer Science in Tsinghua University has initiated a Theory Day program, a one-day public workshop to be held each semester. This program is intended to communicate some of the exciting latest research results in theoretical computer science, especially those carried out in China. The talks are designed to convey the essence of the work, not only to the experts but also to the computer science community at large. Whether you are a specialist in this area, you will find the program stimulating.

The Theory Day inaugural program will be this Wednesday. Three brilliant young scientists of our institute will share their research results and insights with you. They are Dr. Xiaoming Sun (who graduated from our Institute in 2006), Xi Chen (fourth-year graduate student), and Pinyan Lu (second-year graduate student). Xiaoming’s research interests include quantum computing, quantum information and classical complexity. Xi’s interests lie in characterizing the computational complexity of natural problems in Algorithmic Game Theory and Computational Biology. And Pinyan’s interests are in complexity theory, algorithms design and algorithmic game theory.

Tsinghua ITCS Theory Day (II)

time: Apr. 12, 2:00-5:00pm

The Institute for Theoretical Computer Science in Tsinghua University has initiated a Theory Day program, a one-day public workshop to be held each semester. This program is intended to communicate some of the exciting latest research results in theoretical computer science, especially those carried out in China. The talks are designed to convey the essence of the work, not only to the experts but also to the computer science community at large. Whether you are a specialist in this area, you will find the program stimulating.

The Theory Day program II will be this Thursday. Three scientists will share their research results and insights with you. They are Professor Mike Paterson (who is a Professor of Department of Computer Science, University of Warwick, Coventry, CV4 7AL, United Kingdom), Professor Mario Szegedy (Rutgers University) and Professor Ran Raz (faculty of mathematics and computer science at the Weizmann Institute). Prof. Mike Paterson’s research interests include graph theory. Prof. Mario Szegedy’s interests are in complexity theory, combinatorics, combinatorial geometry and quantum computing. And Prof. Ran Raz’s interests lie in Boolean circuit complexity, Arithmetic circuit complexity, Communication complexity, Propositional proof theory, Probabilistic checkable proofs, Quantum computation and communication and Randomness and derandomization.

[tags]TCS, theory day[/tags]

© zhiqiang for 阅微堂, 2007. | 链接 | 1条评论