Page 1 of 8 ID# Exam1 PS 306, Spring 2006 The Skidmore Honor Code is in effect for this exam, as always. You’ll be asked to write out the Honor Code statement at the end of the exam. Read each question carefully and answer it completely. Show all your work, so that you may receive partial credit. Keep in mind that a point is roughly equal to a minute, so don’t spend too much or too little time on your answer to any question. Good Luck! 1. Dr. I. P. Freeley was interested in replicating the Middlemist et al. study (effect of invasion of personal space on time to urinate), but using a repeated measures design for greater power. For several days, he had a rotating cadre of confederates (so that the students wouldn’t think that someone was stalking them) follow a set of students enrolled in an introductory psychology class. Whenever one of these students would enter a restroom to urinate, a confederate would check to ensure that no one else was using a urinal. If the participant were alone at one of the urinals, the confederate would either: 1) go to the urinal immediately next to the student (Near Stall); 2) go to a urinal one urinal away from the student (Distant Stall); or would simply go to the mirror and comb his hair (Alone). The dependent variable, as in the Middlemist study, was the time (in minutes) between when the unwitting participant unzipped his pants and when he began to urinate (micturate). Complete the source table below and interpret these data as completely as you can. [10 pts] 10 .550 .227 .07210 .560 .196 .06210 1.140 .259 .082Count Mean Std. Dev. Std. Err.AloneDistant StallNear StallMeans Table for DistanceEffect: Category for DistancePage 2 of 8 2. Mook argues that external validity is not always the purpose behind psychological research. For each of the studies below, indicate why the study is not externally valid, then why it’s not a concern, given the intentions of the researcher(s). [10 pts] Study Why not externally valid Why lack of EV is not a concern Argyle (glasses and intelligence) Harlow (infant monkeys and drive reduction theory) Hecht (dark adaptation) Brown & Hanlon (parental role in grammar acquisition)Page 3 of 8 3. Correlational designs do not allow you to make casual claims. Why not? Be very explicit about the difficulty of claiming that changes in one of the two variables in a correlational study causes the related changes observed in the second variable. We also discussed the shortcomings of using non-manipulated characteristics of the participants as “independent variables” in an experiment. How is this class of variable related to the notion of correlational designs? [10 pts]Page 4 of 8 4. Two researchers were interested in studying the effects of reward magnitude on performance. Both researchers used introductory psychology students as participants, the same total number of participants (21), the same type of reward and reward magnitudes ($1, $5, $20), the same apparatus, the same task, and the same performance measure (DV). One researcher used an independent groups design and, on the basis of the results, cannot reject the null hypothesis (that reward has no effect on performance). The other researcher used a repeated measures design and found a statistically significant effect of reward magnitude — larger rewards lead to better performance. Assume that neither study has a major flaw (e.g., repeated measures design is properly counterbalanced, random assignment to conditions). There are two fundamental reasons why the two researchers might have reached different conclusions. One reason concerns the sensitivity of the test of the null hypothesis. The other reason concerns the nature of the participant’s experience in the two studies. Provide me with a clear explanation of the two reasons for the different results that the two researchers obtained. Would you trust the results of one study more than the other? Why? Finally, complete the source tables for the two experimenters seen below. [10 pts] Independent Groups Design (FCrit = 3.55): Source df SS MS F Treatment 28 Error Total 100 Repeated Measures Design (FCrit = 3.23): Source df SS MS F Subject 100 Treatment 20 Error (Subj x Treat) Total 200Page 5 of 8 5. In your first lab, there were a number of different personality measures. One was the Rosenberg Self-Esteem Scale (selfestm) and another was the Satisfaction with Life Scale (swls). Had you correlated those two measures, you would have seen an output like the one below. Interpret the output below as completely as you can. If a person had a self-esteem score of 30, what would you predict that person’s SWLS score to be? What proportion of variance do these two measures share? If you were to talk about this result in a Discussion, what might you say about the relationship? [10 pts] 330.737.543.5284.571CountNum. MissingRR SquaredAdjusted R SquaredRMS ResidualRegression Summaryswls vs. selfestm1 769.876 769.876 36.851 <.000131 647.639 20.89232 1417.515DF Sum of Squares Mean Square F-Value P-ValueRegressionResidualTotalANOVA Tableswls vs. selfestm-8.202 5.329 -8.202 -1.539 .13391.081 .178 .737 6.071 <.0001Coefficient Std. Error Std. Coeff. t-Value P-ValueInterceptselfestmRegression Coefficientsswls vs. selfestm5101520253035swls15 17.5 20 22.5 25 27.5 30 32.5 35 37.5selfestmY = -8.202 + 1.081 * X; R^2 = .543Regression PlotPage 6 of 8 6a. First of all, imagine a repeated measures design with seven levels. Can you tell me why you’d need to counterbalance such a design, what kind of counterbalancing you’d use, and how many participants you’d need? What is the impact of counterbalancing on order and carry-over effects? [3 pts] 6b. OK, now let’s assume that there is a particular order effect — a practice effect. That means that scores on the DV will improve over time as a result of practice. What is the impact on your error term (MSError) of counterbalancing? [2 pts]Page 7 of 8 7. In Lab 2, you saw a set of photo-arrays. As you know, each participant in that study rated each of the faces on the extent to which that face was a match for the eyewitness description (1 = “Poor Match” to 7 = “Great Match”). If the photo-array were unbiased, then the ratings of the six faces would be similar. To the extent that some faces were rated as less similar to the eyewitness description, then they were not really fair