http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Random samples and representative samples
1 online resource (1 video file (00:07:30)) : sound, colour.
Billy Jack explains how to randomly assign individuals to groups in a randomized controlled trial (RCT) and discusses the importance of random assignment for making causal inferences.