The first video in Pew Research Center’s Methods 101 series helps explain random sampling – a concept that lies at the heart of all probability-based survey research – and why it’s important. Fresh ...

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 ...

Hydrologists from the Department of Energy's Pacific Northwest National Laboratory are using a simple apparatus of quarter-inch-diameter plastic tubing to collect samples at varying levels in the ...

Considerable controversy has taken place between those who favor quota sampling and those who advocate area sampling in opinion polling. This article does not attempt to give a final solution to the ...

A study by the universities of Cordoba and Seville develops a method that makes it possible to verify, easily and quickly, whether an olive plantation is traditional, intensive, or super-intensive.