Learn how representative samples and random samples differ and why combining them minimizes sampling bias for accurate data.

Discover how to determine the ideal percentage of a population for a representative sample to ensure accurate data analysis with minimal sampling error.

Sampling allows archaeologists to draw conclusions about a site or region using only a fraction of the area. Because excavation is destructive and funding is limited, leaving parts unexcavated can be ...

Note: This report was updated on Dec. 30, 2015 to reflect the January-July 2015 National Health Interview Survey estimates released on December 1, 2015. Telephone surveys face numerous challenges, but ...