GMAT 逻辑分析题 (24)

sdcar2010

Wall Street analyst: A recent study pitted a seasoned, highly skilled Wall Street trader against a computer program to predict stocks price of 100 companies based on their previous historical data. The "competition" lasted for 5 consecutive trading days . In the end, the computer program correctly predicted a significantly higher proportion of the stocks that were later confirmed to be rising than did the trader. Therefore, stock price prediction should be left to computer programs.

Which one of the following, if true, most weakens the above argument?

A) The trader in the study was unrepresentative of traders in general regarding skill level and experience level.
B) Trading stock is as much a test of guts as a battleground for analytical abilities, and computer programs are not easily adapted to making risky but potentially highly rewarding decisions.
C) The trader correctly predicted a significantly higher proportion of the stocks that were later confirmed to be falling than did the computer program.
D) In a considerable percentage of stocks, historical data of stocks alone are not sufficient to enable either computer programs or traders to make accurate predictions of stock price.
E) Experts admitted that the trader made fewer obvious mistakes in interpreting the historical data of stocks than did the computer program.

Politician

B???

Politician

Please correct my logic because I did find some problem with this Q.

The premise is that PC is more proficient in forecasting rising stocks, and it is derived that PC should be adopted instead of men.

I personally think both C&B can survive; they all tell us sth human analyst don't share with the PCs.But unfortunately I cannot tell which one is better.

eliasfan

I think C is best
B is strengeh

sdcar2010

Good work!

C is the answer.

Let's say there are 100 companies to be evaluated, half of them with rising stocks and half of them with falling stocks. The computer predicted correctly 49 of the rising stocks but only 2 of the falling stocks while the trader predicted correctly 40 of the rising stocks but 40 of the falling stocks.  Overall, the company is right 51% while the trader is right 80%!

dwane1113

我也选的C，但是在A的地方有点小小的hesitation.A为什么不能说明调查不具代表性呢？

sdcar2010

我也选的C，但是在A的地方有点小小的hesitation.A为什么不能说明调查不具代表性呢？

-- by 会员 dwane1113 (2010/12/12 0:34:36)

In this case, we need the BEST trader against the Best computer program, not an average one in either category.

月照琳琅

get it.

karenchan

in my opinion, the focus of B rests on the latter part of the sentence, "but......", to some extent, it strengthen the conclusion~

happyhxl

我怎么觉得b是无关选项呢。文章说prediction而b说make decision的啊。我错选了a。疯了！怎么办，要抓狂了！