Question: Describe two types of research designs used when we select related samples.
• In a related sample, participants are related. Participants can be related in one of two ways: They are observed in more than one group (a repeated-measures design), or they are matched, experimentally or naturally, based on common characteristics or traits (a matched-pairs design).
• The repeated-measures design is a research design in which the same participants are observed in each treatment. Two types of repeated-measures designs are the pre-post design and the within -subjects design.
• The matched -pairs design is a research design in which participants are selected, then matched, experimentally or naturally, based on common characteristics or traits.