Learn the distinctions between simple and stratified random sampling. Understand how researchers use these methods to accurately represent data populations.

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 ...

Nosocomial infections are infections that are acquired while at a health care facility and are not present at the time of admission. Nosocomial infections are many times also called hospital acquired ...