Wondering how many people in the United States have a smartphone? If you poll 20 people on the street, your survey won’t be representative of the entire American population. But if you just want to ...

Oct. 8, 2008— -- Surveys based on a random sample of respondents are subject to sampling error – a calculation of how closely the results reflect the attitudes ...

This article originally appeared on Undark. When pollsters, journalists, and pundits want to signal that an opinion poll may not be right on target, they often turn ...