A sampling error is a statistical error that occurs when a sample does not represent the entire population. See how to avoid sampling errors in data analysis.

Learn about representative samples and how they are used in conjunction with other strategies to create useful data with manageable sample sizes.

Population adjustments. For each type of survey, we have a preferred sample population — for example, likely voters for horse-race polling or all adults for presidential approval.

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 ...