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

The next sample design for the customer satisfaction survey uses stratification by State. The sampling frame is also sorted by Type and Usage before sample selection, to provide additional control ...

Adam Hayes, Ph.D., CFA, is a financial writer with 15+ years Wall Street experience as a derivatives trader. Besides his extensive derivative trading expertise, Adam is an expert in economics and ...

Several states with extensive water use databases rely upon the census approach. That is, data are collected for all water users withdrawing amounts greater than a specified threshold that varies from ...