GMAT考试-Testprep数学精解(10)

American auto market， GM surveyed owners of GM cars and asked them whether t

hey would be more willing to buy a large， powerful car or a small， economica

l car. Seventy percent of those who responded said that they would prefer a

large car. On the basis of this survey， GM decided to continue building larg

e cars. Yet during the'80s， GM lost even more of the market to the Japanese

……

Which one of the following， if it were determined to be true， would best exp

lain this discrepancy.

（A） Only 10 percent of those who were polled replied.

（B） Ford which conducted a similar survey with similar results continued to

build large cars and also lost more of their market to the Japanese.

（C） The surveyed owners who preferred big cars also preferred big homes.

（D） GM determined that it would be more profitable to make big cars.

（E） Eighty percent of the owners who wanted big cars and only 40 percent of

the owners who wanted small cars replied to the survey.

The argument generalizes from the survey to the general car-buying populatio

n， so the reliability of the projection depends on how representative the sa

mple is. At first glance， choice （A） seems rather good， because 10 percent d

oes not seem large enough. However， political opinion polls are typically ba

sed on only .001 percent of the population. More importantly， we don't know

what percentage of GM car owners received the survey. Choice （B） simply stat

es that Ford made the same mistake that GM did. Choice （C） is irrelevant. Ch

oice （D）， rather than explaining the discrepancy， gives even more reason for

GM to continue making large cars. Finally， choice （E） points out that part

of the survey did not represent the entire public， so （E） is the answer.

Analogy

To argue by analogy is to claim that because two things are similar in some

respects， they will be similar in others. Medical experimentation on animals

is predicated on such reasoning. The argument goes like this： the metabolis

m of pigs， for example， is similar to that of humans， and high doses of sacc

harine cause cancer in pigs. Therefore， high doses of saccharine probably ca

use cancer in humans

Clearly， the greater the similarity between the two things being compared th

e stronger the argument will be. Also the less ambitious the conclusion the

stronger the argument will be. The argument above would be strengthened by c

hanging “probably” to “may.” It can be weakened by pointing out the dissimil

arities between pigs and people.

Example：

Just as the fishing line becomes too taut， so too the trials and tribulation

s of life in the city can become so stressful that one's mind can snap.

Which one of the following most closely parallels the reasoning used in the

argument above？

（A） Just as the bow may be drawn too taut， so too may one's life be wasted p

ursuing self-gratification.

（B） Just as a gambler's fortunes change unpredictably， so too do one's caree

r opportunities come unexpectedly.

（C） Just as a plant can be killed by over watering it， so too can drinking t

oo much water lead to lethargy.

（D） Just as the engine may race too quickly， so too may life in the fast lan

e lead to an early death.

（E） Just as an actor may become stressed before a performance， so too may dw

elling on the negative cause depression.

The argument compares the tautness in a fishing line to the stress of city l

ife； it then concludes that the mind can snap just as the fishing line can.

So we are looking for an answer-choice that compares two things and draws a

conclusion based on their similarity. Notice that we are looking for an argu

ment that uses similar reasoning， but not necessarily similar concepts. In f

act， an answer-choice that mentions either tautness or stress will probably

be a same-language trap.

Choice （A） uses the same-language trap——notice “too taut.” The analogy betwe

en a taut bow and self-gratification is weak， if existent. Choice （B） offers

a good analogy but no conclusion. Choice （C） offers both a good analogy and

a conclusion； however， the conclusion， “leads to lethargy，” understates the

scope of what the analogy implies. Choice （D） offers a strong analogy and a

conclusion with the same scope found in the original： “the engine blows， th

e person dies“； ”the line snaps， the mind snaps.“ This is probably the best

answer， but still we should check every choice. The last choice， （E）， uses l

anguage from the original， “stressful，” to make its weak analogy more tempti

ng. The best answer， therefore， is （D）。