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

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

One possible explanation for the variability in estimates across the different nonprobability samples is the range of methods that online sample vendors employ. They differ on recruitment, weighting ...

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 ...

Cochran (1977) outlines eleven steps in the planning of a survey. Good sampling methods must exist in the environment of all of these steps. These steps are (1) a statement of the survey objectives, ...

The method of systematic random sampling (METHOD=SYS) selects units at a fixed interval throughout the sampling frame or stratum after a random start. PROC SURVEYSELECT chooses the first unit randomly ...