LSAT－18－2－5

swimmingfrog

5.     All 250 of the city’s Democratic ward leaders were polled about the number of registered Republicans who became registered Democrats during the year. From the reports of the 20 leaders who replied to the questionnaire, we know that altogether they received a total of 500 former Republicans into the Democratic party within the year. Projecting from this sample, we conclude that at least 6,000 Republicans became Democrats during the year.

Which one of the following statements, if true, most clearly undermines the conclusion?

(A) Several years ago, 5,000 members of the Republican party registered as Democrats.

(B) The more than 90 percent of ward leaders not replying had no former Republicans registering as Democrats.

(C) Because they were too busy, more than 90 percent of the ward leaders did not reply.

(D) A number of the newly registered Democrats returned to the Republican party at a later date.（B）

(E) Similar figures can be produced from past years for registration changes from the Democratic party to the Republican party.

All 250 of the city’s Democratic ward leaders were polled about the number of registered Republicans who became registered Democrats during the year.

I don't understand this sentence, besides those numbers puzzled me a lot!

[此贴子已经被作者于2004-12-23 14:24:40编辑过]

hedonism555

the speaker takes for granted that the poll on 20 democratic leader is representitive fo all the 250, therefore, deduct that ( 250/20 )*500= 6250= at least 6000.

B weaken it by saying the other 90% leaders have no tranfered republicants .

swimmingfrog

sorry ,我整个句子都挺胡涂，250个民主党领导were polled about 注册共和党的人数（这些共和党今年变成注册民主党）

poll 我知道是竞选，可搞不清楚说选谁？怎么这个变成那个的，乱！！

hedonism555

就是调查变节分子的人数。

Bensontuo

swimmingfrog 发表于 2004-12-23 14:14
5.     All 250 of the city’s Democratic ward leaders were polled about the numb ...

Spot the question type: weaken

20/250 said they received 500 R a year. So, at least 6,000 R During that year.

He must take for grant that if 20 of D is a set, then 12 sets of D must be referring to different R. Thats how he support the claim that there must be at least ( 500 * 12 ) R.

However, what if from those 12 sets, they are referring to the same group of R ?

By the same token, does that 20 of D could be perfectly represent the total 250 D ?

Let us see the question

A. Not relevant

B. This one is kinda tricky, and which is to say, we do not know how many percentage of no reply from 250 D, so we dont know how many actually do reply to the survey, If that's the case, then we do not know whether 20 is totally representable or not. By the same token, if none of them do have FR registered as D, then we must know that Great possibilities could exist that it must be less than 6,000.

C. 90% did not reply could only prove that the sample might be incorrect ( Flaw ); however, having the flaw within the methodology of obtaining the evidence to support the conclusion does not exactly man that the conclusion itself must be wrong.

D. Not relevant

E. Not relevant.