ABSTRACT
In this chapter, the author reviews some concepts related to designing quantitative research. They begin with an overview of sampling issues and sampling strategies, and then discuss basic concepts in research design, including definitions and terminology. In the sampling method a researcher selects the sample using their experience and knowledge of the target population or group. Key term in research design is random assignment. In random assignment, everyone in the study sample has an equal probability of ending up in the various experimental groups. Random assignment matters for the kinds of inferences a researcher can draw from a given set of results. By randomly assigning participants to groups, theoretically their background characteristics and other factors are also randomized to groups. Sometimes researchers develop several forms of the same test to allow them to administer it several times without worrying about practice effects. Many neuropsychological tests for things like memory or academic achievement tests have alternate forms.
