Romney campaigned Thursday in Florida, where two nonpartisan live operator polls conducted over the past two weeks both indicate Obama has a five-point advantage, which is within the surveys' sampling errors.

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The reason for this seemingly dotty result is that the errors from scientific sampling are easier to quantify (and minimise) than those arising from an imperfect head-count.

ECONOMIST: Statistics

Although sampling can also lead to errors if, for instance, the characteristics of the sample group differ from those of the population from which the sample is drawn the errors will be smaller and can be measured more precisely.

ECONOMIST: Statistics

As students, you should keep in mind that all these numbers are estimates based on samples, which are thus subject to sampling error (as well as other types of errors).

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