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 ...

Determination of sample size is one of the critical decisions in forming a customer survey. Though you can find numerable statistical guides, and sample size calculators available, many people find ...

An explanation of the methodology for 538's current polling averages. 538 goes through many steps to calculate its polling averages. ABC News Photo Illustration This is an old version of our polling ...