再发一道对PREP不一样的分析..还是不知道自己的分析对不对...求斑斑或NN指点迷津

DUKB24

Bank depositors in the United States
are allfinancially protected against bank failure because the government insures allindividuals' bank deposits.  An economistargues that this insurance is partly responsible for the high rate of bankfailures, since it removes from depositors any financial incentive to find outwhether the bank that holds their money is secure against failure.  If depositors were more selective, then bankswould need to be secure in order to compete for depositors' money.The economist's argument makes which of the following assumptions?

(A)Bank failures are caused when big borrowers default on loan repayments.
(B)A significant proportion of depositors maintain accounts at several differentbanks.
(C)The more a depositor has to deposit, the more careful he or she tends to be inselecting a bank.
(D)The difference in the interest rates paid to depositors by different banks isnot a significant factor in bank failures.
(E)Potential depositors are able to determine which banks are secure againstfailure.这里高智威讲解的说是本文最后一句的if语句代表本文的最后一个推导，所以就着重分析最后一个推导，它就说跟第一个推导的关系假设有关系，但是和最后一个没关系的也要排除，就是D选项咯..
但是我觉得既然题干说了是关于经济学家的argument，应该两个都要分析吧..
好吧先diagram一下：
premise1：the insurance removes from depositors any financial incentive to find out whether the bank that holds their money is secure against failure
conclusion1： this insurance is partly responsible for the high rate of bank failures


premise2：if depositors were more selective
conclusion2：then banks would need to be secure in order to compete for depositors' money..
以下就只分析DE选项，ABC都很明显是irrelevant.
对D选项，取非，利率的不同是一个significant的factor.（貌似这个比较针对第一个结论，但是没有削弱，应该结论说了是partially liable）
对E选项取非，投资者不能决定哪个银行是安全或者危险的..
这样的话第一个结论就不成立了，因为取非后直接攻击的premise1，证明因果关系不存在？说明insurance不是造成人们不选择的原因而是人们自己本身就不能选择..
第二个结论就更明显了，他们不能甄别哪个银行好，那银行肯定就不会去need to be secure去compete 他们的money
这题。。。这个，以上就是我的分析，不知道对不对，求NN们或者斑斑指点迷津一下...

DUKB24

求NN！

DUKB24

DUKB24

DINGDINGDING

sdcar2010

The conclusion is: If depositors were more selective, then banks would need to be secure in order to compete for depositors' money.

D) talks about factors in bank failures, which is not reflected anywhere in the above conclusion.

Further, I do not know how would you came up with your first conclusion: this insurance is partly responsible for the high rate of bank failures.  There seems no trigger for that in the passage. (I got it now). My bad.

cherryzxj

The conclusion is: If depositors were more selective, then banks would need to be secure in order to compete for depositors' money.

D) talks about factors in bank failures, which is not reflected anywhere in the above conclusion.

Further, I do not know how would you came up with your first conclusion: this insurance is partly responsible for the high rate of bank failures. There seems no trigger for that in the passage.

-- by 会员 sdcar2010 (2012/5/6 4:22:46)

I'm so glad to see that it is you to answer this question, since I've read all your 逻辑入门 which
taught me so much.
But I'm puzzled at this question:
1.  I think, conclusion: this insurance is partly responsible for the high rate of bank failures because the word "since" is right after the comma, but I don't know the last sentence plays what role.
2. I don't know whether the question requires us to look for the sufficient assumption or necessary one?
3. I use your method to look for the gap:
conclusion:insurance --->bank failure
premise:    insurance ---> no select which bank is secure
                    然后我就不知道该怎么写了。。呜呜。。求指教啊！！！！

sdcar2010

Bank Depositors in the United States are all financially protected against bank failure because the government insures all individuals' bank deposits (Background). An economist argues that this insurance is partly responsible for the high rate bank failures, since it removes from the depositors any financial incentive to find out whether the bank that holds their money is secure against failure (Premise 1). If depositors were more selective (Premise 2), then banks would need to be secure in order to compete for depositor's money (conclusion).

sdcar2010

Choice E) is almost a slam dunk if your use the negation method.

If E) is wrong, then a depositor would NOT be able to determine which bank is secure against failure (all by him- or herself).  If this is true, then EVEN IF the the dpositor is more selective (thus, looks for indicators about bank security issues), he would NOT be able to tell which bank is safer!  Thus the mail conclusion falls apart.