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Final Exam Short Answers This course gives you the final answers that are the same throughout the years of the course. There is 10 given short answers worth 5 points (4 will be on exam) and 4 long answer questions worth 10 points (1 will be on exam)

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John Holmes

3.What are three purposes of factorial designs? Illustrate one of those purposes with a graph example, carefully labelled. Interactions can help us understand the HOW and WHY of things • Measure the simultaneous effects of multiple variables • Answering why/how: Identify mechanisms • Answering WHEN effects occur – identifying critical conditions • Answering WHEn something still occurs; some reactions are only apparent in CERTAIN contexts – certain times when • Block desigsn and generalizations across population 4.Describe the nature of a terminative interaction in plain English. In addition, provide a brief example and draw a rough graph to illustrate the pattern of results. • part of the triangle group • Either treatment produces an effect • No benefit in combining 2 treatments 5.Describe the nature of a catalytic interaction in plain English. In addition, provide a brief example and draw a rough graph to illustrate the pattern of results. • part of triangle group • combination of both treatments are necessary to produce an effect • 2 main effects 6. Explain as if to a 10-year-old child the concept of random assignment and why scientists find it so useful for establishing that X causes Y (i.e., do not use words that a 10-year-old would not understand). • Random assignment is useful for scientists to determine that X causes Y because it makes sure that o everyone in all conditions of the experiment are all roughly the same, and o any differences between them will cancel each other out. 7. Explain the logic of the post-test only true experiment. That is, how can a researcher conclude that one group changed if there was no pre-test, and how can he/she confidently attribute the change to the i.v.? • PTPT groups are susceptible to many threats to intrernal validity that are time related including: maturation, testing, instrumentation, regression to the mean • Post test only effectively eliminates these threats because they are not tested twice, they are only tested once • Since you are testing two groups, the difference can be attributed to the IV o That is the logic behind the Post Test only o In the event that the IV did NOT occur, the results should be the same, but since the time related threats are eliminated, we can conclude any difference is due to the manipulation of the IV 8 A researcher wants to see whether a positive self-talk program raises self-esteem. He/she recruits people from the community with extremely low self-esteem (as indicated on a measure of self-esteem) to participate in a pretest-posttest true experimental design. For the following threats to internal validity, describe whether the design is vulnerable or invulnerable to the threat and why: regression to the mean and testing. • Regression to the mean – vulnerable – may occur . can’t explain different b/w groups o Possible that participants will regress to the mean during post test • Testing – vulnerable – may occur but can’t explain difference between groups o Possible that during the post testing, participants may be conditioned to know that they are being tested, influencing test scores. 9. Describe three disadvantages or limitations of true experiments. (The more different your three points are from each other, the better your mark will be.) o Might be too perfectly controlled that it does not reflect real world scenarios o Difficult to exclude outside factors like third variables and confounds o It is hard to tell if a subject will act “naturally” under an experiment 10. Explain the difference between a mediator and a confound (you should describe what a mediator is and what a confound is, and explain how these two things differ). Describe a possible mediator and a possible confound in the following study: A researcher is interested in the effects of being flirted with on helping behavior. She hypothesizes that people who have just been flirted with are more likely to help another person. She randomly assigns males studying in a library to a flirt or a no flirt condition. She approaches each male participant in the flirt condition and says "Is it hot in here or is it just you?" She does not approach participants in the no flirt condition. A few minutes after flirting with the participant (or not), the researcher approaches each participant and asks him to make a donation to a charity. Her results are as predicted: Participants in the flirt condition are more likely to donate than participants in the no flirt condition. • A mediator is a variable that explains why two variables are related. • A confound is a variable that does not explain why the two variables are related, but rather explains why the two may covary. It also varies with both the IV and the DV. • A mediator in this study could be that increased interpersonal rapport increases the likelihood of helpful behaviour. A confound in this study could be that the atmosphere? 10-point questions. One of these will appear on the final exam. 1. Define the three requirements for establishing causality in research. For each requirement, explain how a researcher using a correlational design can address it to draw the strongest conclusions possible about causality, explain how a true experiment does or does not address each requirement, and which design is superior at addressing the requirement and why. • The three requirements for establishing causality in research are: o Temporal Order – o
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