GMAT考试写作指导：Argument范文二二

　　82. In this editorial the author asserts that opinion polls are little better than random

　　guesses to predicting outcomes of presidential elections. The authors basis for this

　　assertion is that opinion polls measure only the preferences of voters at the time of the

　　poll and that many voters change their preferences several time before voting―some

　　remaining undecided until the moment they cast their vote. The authors reasoning is

　　unconvincing in two critical respects.

　　First of alt the predictions based on random guessing are such that the greater the

　　number of candidates, the less likely the prediction will be correct. The reason for this is

　　obvious: random guessing requires that no outside information be allowed to influence

　　the guess. Predictions based on opinion polls, on the other hand, will differ considerably

　　from those based on random guesses simply because outside information will influence

　　the result. For example, in a four-person race, random guessing would yield the correct

　　prediction 25 percent of the time, whereas the percentage of correct predictions based

　　on opinion polls would be much higher. The reason for this disparity is simple. Opinion

　　polls enable us to narrow the choices. That is, opinion polls serve to reduce the number

　　of viable candidates in the voters mind and thereby increase the likelihood that the

　　prediction based on them will be correct.

　　In addition, while it is true that many voters change their minds several times

　　before voting, and that some remain undecided until entering the voting booth, this is

　　not true of everyone. Moreover, people who do change their minds frequently or wait

　　until the last moment to decide have typically narrowed their choice to a few candidates

　　In conclusion, the author is mistaken in believing that random guessing would be

　　as reliable as opinion polls in predicting the outcomes of presidential elections.