【英语时差8,16】公众投票的误差及可信度（上）

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Pollsters looking for the opinion of the American public obviously can’t survey everyone. But by surveying a smaller, random¹ sample of the population they estimate the views of the whole population. The larger the sample, the more accurate the estimate is likely to be, but the results of every survey also include a second estimate as to the accuracy of the results. Along with the primary result of the survey, you often hear what is called “the margin² of error.” Imagine the following announcement: “Gallup poll finds seventy-five percent of Americans, plus or minus five percent, prefer hamburgers to hot dogs.” Headlines often ignore the “plus or minus five percent,” but that margin of error tells you how exact the results are. In this case, we learn that somewhere between seventy and eighty percent of Americans prefer hamburgers.

 

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