PSY550 Final Exam 2022 With Correct Answers Graded A+

6.QUESTION: Describe a two-matched groups design. How is the matching done? Your Answer: A two-matched sample design is a within-subject design where participants are matched due to a variable either experimentally or naturally based on pre-existing traits for example, two men aged 45. Matching is done by looking at a variable and how that variable may impact the dependent variable. For each participant pair, one individual is assigned to the experimental group and the other to the control group. 7. QUESTION: Chuck Wagon is very excited about the within-subjects approach. “Now I’ll never need to run large numbers of subjects again,” he says. However, Chuck has forgotten that within-subjects designs may be a) useless, b) impossible, c) confounded by order effects, or d) impractical when excessive subject time spent in an experiment makes data inaccurate. Give an example of each of these four objections. Your Answer: 1. USELESS: A within-subjects design would be useless if as an individual is asked to perform a memory test after swimming, and a memory test after meditation. Individuals participating in the study may skew the results because they are better at taking the memory test the second time around. 2. IMPOSSIBLE: An example of an impossible within-subjects design is a study would be surgical treatment vs drug treatment because it is impossible to give both treatments to the study participant. In this instance, it would be either or, not both. 3. CONFOUNDED BY ORDER EFFECTS: Order effects can be confounding variables because they cause changes in the dependent variable from one treatment condition to the next that are not due to the treatment alone. For example, memory testing after meditation, then after yoga, then after swimming, could cause behavior changes in the participant yielding inaccurate results. 4. IMPRACTICAL: If a study takes an excessive amount of time this can make the study data inaccurate due to study participants become tired, fatigued, bored, or restless. For example, memory testing after meditation, then after yoga, then after swimming, then after jogging could cause fatigue in the participant yielding inaccurate results. 8. QUESTION: A researcher has studied subjects’ ability to learn to translate words into Morse code. He has experimented with two treatment conditions: in one condition, the subjects are given massed practice; they spend 8 full hours on the task. In the other condition, subjects are given distributed practice; they also spend 8 hours, but their practice is spread over four days, practicing 2 hours at a time. After the practice, all subjects are given a test message to encode; the dependent variable is the number of errors made. The researcher has matched the subjects on intelligence. The results are in the following table. Decide which statistical test would be appropriate, carry out the test, and evaluate the outcome. Assume a significance level of .05 and that the direction of the outcome has not been predicted. Answer: The statistical test that should be used in this example would be a paired t-test using the following equation: D ∑¿ /N ¿ ¿ ¿ t=−1.∨−1.58 Where t = -1.58 and the value for p = 0.19. With the given significance level of 0.05, the results in this case would not be found to be significant. 9. QUESTION: Explain the pros and cons of longitudinal, cross-sectional, and sequential designs. Answer: Longitudinal design: is a developmental research design used to study changes across the lifespan by observing the same participants at different points in time and measuring the same dependent variables at each time. For example, Terman’s infamous study “Genetic Studies of Genius” the longest running longitudinal study in history. a. Pro: The advantage of this kind of study is that changes in participant behavior can be observed over time, other relationships between variables may be found, allows for large collection of data, and patterns between variables are easy established. b. Con: These types of studies are prone to threats of internal validity. They can be expensive, participant attrition can be high