Prep Guide #6 - for bryan saville PDF

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Research Methods

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PREPARATION GUIDE #6 Based on: Smith & Davis (Ch. 7) Review from previous prep guides: 1. What three criteria must be in place for a researcher to be able to say that one variable caused changes in another variable? With descriptive research methods, can you infer cause-and-effect? Explain your answer. a. Three criteria for cause and effect i. Temporal precedence (cause occurs before the effect) ii. Covariation of events (events correlated) iii. Eliminated plausible alternatives b. With experiments you can infer cause and effect because you see the relationship between the IV (cause) and the DV (effect) S & D (Ch. 7) 2. Why should you consider within-group variability when determining which and how many participants to use in your study? How does this consideration affect the power of a statistical test? Finally, how is the number of participants you use in a study related to power? a. The less the within-group variability (i.e., the more homogeneous the participants), the fewer participants we will need. i. Less participants= less power b. The greater the within-group variability (i.e., the more heterogeneous the participants), the greater the number of participants we will need. i. More participants= more power c. Using a larger sample provides more information about the population and, thus, increases power 3. What are Rosenthal effects? Explain how a researcher’s expectations can unknowingly function as an EV and confound the results of a study. As such, do you think that stating a hypothesis before you conduct an experiment could possibly be a bad idea? Explain. a. Rosenthal effect implies that a researcher, convinced of his hypothesis, might unconsciously influence the outcomes of his experiments in a way consistent i. Even though hypothesis influence an experiments outcome, we cannot not state them. To alleviate the issue, we should make them nondirectional, so we have less bias b. Researcher’s expectations act as an extraneous variable and confound because they are additional factors that influence the dependent variable, outcome, of the study 4. Explain how participant perceptions might affect the results of a study. How can a singleor double-blind study control for experimenter expectancies and participant perceptions? a. Participants believe they must behave in a certain manner, becoming an EV/confound

Research Methods

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b. demand characteristic: a subtle cue that makes participants aware of what the experimenter expects to find or how participants are expected to behave c. The desire to cooperate and act as the participants believe the experimenter wants them to is called the good participant effect d. yea-sayers/nay-sayers, who say yes to all questions, pose a threat to psychological research (threatens validity) e. A response set is the human tendency to answer questions in ways that are the most complimentary to the respondent rather than telling the absolute truth f. Single-blind experiment: An experiment in which the experimenter (or participants) is unaware of the treatment the participants are receiving. i. Minimizes experimenter expectancies since they aren’t sure who is and isn’t receiving treatment ii. The experimenter truly does not know what treatment condition is being administered in single-blind experiments of this nature. g. Double-blind experiment: An experiment in which both the experimenter and the participants are unaware of which treatment the participants are receiving. i. Minimizes experimenter expectancies since they aren’t sure who is and isn’t receiving treatment ii. May minimize participants, but some will still have perceptions and act accordingly 5. Betsy is very excited because she believes she has found a new and superior method for teaching research methods to psychology majors. In fact, she suspects that her method will prove to be significantly better than more traditional methods. Starting next week, she plans to recruit two groups of students to take part in a study that is designed to prove that her method is better than other methods. She will teach both groups, one with the new method and one with a more traditional method, and examine whether students in the “New” condition learn faster than students in the “Traditional” condition. What type of research design is Betsy using? What is her IV? Her DV? At the end of her study, if she appropriately controls for EVs, can she infer causation? Explain your answer. Experiment, IV: teaching method, DV: material learned, she can explain causation because she can see how teaching methods affects learning What is her research hypothesis? Is it directional or nondirectional? Directional hypothesis: she suspects that her method will prove to be significantly better than more traditional methods What is a big EV in the above scenario that could potentially affect the results of her study? How could she control for this EV? The EV is her bias, she could influence the results. To control his EV she could do a single blind study and have someone else teach, and not tell the participants which group they are a part of...