Experimental Designs Show
The Uniqueness of Experimental Methodology Experimental Control Determination of Causality Internal versus External Validity Another advantage of a well-designed experimental method is its high level of internal validity. A design that has high internal validity allows you to conclude that a particular variable is the direct cause of a particular outcome. In contrast external validity is often seen as a challenge for experimental work. External validity is the degree to which conclusions drawn from a particular set of results can be generalized to other samples and situations. The sample in a particular experiment may not represent the larger population of interest, and the experimental situation may not resemble the real-world context that it is designed to model because of its artificiality. The concern around artificiality is controversial and not shared by everyone who does psychological research. Key Constructs of Experimental Methods Independent and Dependent Variables Experimental
and Control Groups Placebo Effect Random Assignment Types of Experimental Designs Between-Subjects Designs Advantages of Between-Subjects Designs Disadvantages of
Between-Subjects Designs Within-Subjects Designs Advantages of Within-Subjects Designs Disadvantages of Within-Subjects Designs Matched Group Designs Advantages of Matched Group Designs Disadvantages of Matched Group Designs Confounding Factors and Extraneous Variables Participant Characteristics The Hawthorne Effect Demand Characteristics Other Confounds Strategies for Dealing with Confounds Hold Potential Confounding Variables Constant Vary Test Items and Tasks Use Blind and Double-Blind Designs Statistically Control for Variables that Can’t be
Experimentally Controlled Use Randomization and Counterbalancing Ceiling and Floor
Effects What Steele and Aronson Found Ethical Considerations in Experimental Design Placebo/Control Group and Denial of Treatment Confederates and Deceit Why do researchers use random assignment when determining which research participants will comprise the different treatment groups in the study quizlet?Why is it important to use random assignment when determining which research participants will comprise the different treatment groups in the study? Random assignment balances out the differences that might naturally exist between participants.
Why is it important to use random assignment?Random assignment enhances the internal validity of the study, because it ensures that there are no systematic differences between the participants in each group. This helps you conclude that the outcomes can be attributed to the independent variable.
Why is random assignment used to assign people to treatment groups and control groups in a controlled experiment?Random assignment of participants helps to ensure that any differences between and within the groups are not systematic at the outset of the experiment. Thus, any differences between groups recorded at the end of the experiment can be more confidently attributed to the experimental procedures or treatment.
Why is it important for researchers to randomize the order that participants go through the different conditions of the experiment?Randomization in an experiment means random assignment of treatments. This way we can eliminate any possible biases that may arise in the experiment. Good. Randomization in an experiment is important because it minimizes bias responses.
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