ID# Exam 2 PS 306, Fall 2003As always, the Skidmore Honor Code is in effect, and you will have to write out theHonor Code and sign it at the end of the exam. Read each question carefully and answerit completely, showing all your work. Allocate your time appropriately (1 point = 1minute). Good luck!1. Dr. Melody Brooks is interested in assessing whether or not people eat more when theyare anxious. She brings her participants into the lab one at a time and places a bowl of 30salted peanuts in front of them, explaining that the participant should feel free to eat asmany peanuts as she or he would like. Dr. Brooks then has half the participants fill out anominous-looking consent form, absolving her of all liability should the experiment resultin permanent damage to the participant. She then tells these participants that they willreceive a series of painful electric shocks (though there will be “no permanent tissuedamage”), to determine their tolerance for pain. The other half of the participants aregiven a standard consent form that simply describes the experiment and asks for theparticipant’s cooperation. Dr. Brooks then tells this group that they will be serving as acontrol group for an experiment and will have to wear a shock electrode and receive amild electric shock, but that it will only feel like a mild tingle. (Dr. Brooks might wellhave seen the same movie you saw at the beginning of the semester.) Neither groupactually receives a shock, with the threat of the different shock levels intended to createdifferent anxiety levels. At the conclusion of the experiment, Dr. Brooks is surprised tosee that there is no difference between the two groups in terms of peanuts eaten (M forthe anxious group = 29.8, M for the non-anxious group = 29.5). What advice would yougive Dr. Brooks about her experiment? Because you want to make the experiment morepowerful, would you suggest using a repeated measures (within subjects) design? [10 pts]2. Dr. Nick O. Thyme was interested in studying the effects of practice on performanceon video games that involve a great deal of eye-hand coordination. He decides toconduct a two-factor mixed design, with amount of practice (3 hours, 6 hours, 12 hours)as the between (independent groups) factor and input device (keyboard, mouse, joystick)as the within-subjects (repeated measures) factor. He uses the score on a novel videogame as the dependent variable. [15 pts]a. Given the design specified above, if Dr. Thyme wants to have a minimum of 20 scoresper cell (condition), tell him how many participants he would need to run.b. Briefly describe a good procedure that Dr. Thyme might use to conduct his study.c. Suppose that he runs the study and finds no main effects or interaction. What wouldyou advise him to change in his study to make it more powerful? Do you think it wouldhelp if he were to run the study as a completely within (repeated measures) design?3. A major research technique in the field of behavioral genetics is to breed animalsselectively on the basis of particular characteristics exhibited by the animals and then toobserve the relative performance of the offspring. Suppose that an experiment isconducted in which three strains of rats are to be compared. One strain was obtained byselectively breeding rats who performed exceptionally well in a maze-learning task (the“bright” rats); a second strain was obtained by selectively breeding rats who performedquite poorly on the same task (the “dull” rats); and a third strain consisted of rats whowere bred without regard for maze-learning performance (the “mixed” rats). One groupfrom each strain was raised under “enriched” conditions, and a second group was raisedunder “impoverished” conditions. The enriched environment consisted of a large cagecontaining objects for the animals to play with; the impoverished environment consistedof a similar cage containing nothing but the bare essentials of rat life (food and waterdispensers). Following six months of exposure to one of the two environments, all of therats were tested in a standard laboratory maze. There were eight rats randomly assignedto each of the six groups. The learning scores (trials needed to learn the maze) arepresented below. Analyze the results as completely as you can, then provide adescription of the findings. [15 pts]8 2.750 1.165 .4128 8.875 2.167 .7668 6.125 2.232 .7898 8.000 2.449 .8668 11.250 3.955 1.3988 9.250 2.712 .959Count Mean Std. Dev. Std. Err.Enriched, BrightEnriched, DullEnriched, MixedImpoverished, BrightImpoverished, DullImpoverished, MixedMeans Table for Learning ScoreEffect: Environment * Breed4a. Individuals who are identified as having an antisocial personality disorder also tend tohave reduced physiological responses to painful or anxiety-provoking stimuli. Ineveryday terms, these individuals show a limited physical response to fear, guilt, oranxiety. One way of measuring this response is with the galvanic skin response (GSR).With GSR, higher scores indicate lower responsivity and lower GSR scores indicategreater responsivity. In the study summarized below, three groups of individuals weretested: Normal Personality, Antisocial Personality, and Agoraphobics. First, briefly tellme why a group of Agoraphobics (or some other clinically diagnosed group) would beincluded in such a study:As you can see, a third of each group is given the GSR under ordinary circumstances(baseline), a third is given a moderately stressful situation, and a third is given a highlystressful situation. Complete the source table and interpret the results of this study ascompletely as you can. [20 pts]4b. What is your best estimate of the population variance (s2) from which these scoreswere selected? [2 pts]4c. Suppose that you were to compute a one-way analysis of variance on these same data,looking only at the group factor. Complete the source table below to show what the one-way ANOVA would look like. [5 pts]SourcedfSSMSFGroup4d. Compare your F-ratios for Group in the Two-Way ANOVA and in the One-WayANOVA. Under which conditions would your F-ratio be larger? Under which conditionswould your F-ratio be smaller? [3 pts]5. Compare a 3x5 completely between (independent groups) and a 3x5 completely withinsubjects (repeated measures) designs to illustrate the efficiency of a repeated measuresdesign. [5