Exam 1 PS 306, Fall 20031. Briefly define the following terms and explain why each term is important to experimental design. [10 pts]floor effectA floor effect occurs when the task (dv) is too difficult, so that scores are less variable andclustered at the low end of the response continuum. As a result, actual differences in theeffect of treatment may be obscured.Type I errorA Type I Error occurs when you reject H0 and you should have retained H0. Of course,you’d never know that you’d committed a Type I Error. You know that the probability ofmaking a Type I Error is a, which is typically set at .05. It’s important to recognize thatwhenever you reject H0, there is a chance that you’ve done so as a result of a Type I Error.random assignment to conditionsIn an independent groups design, you would run a participant in each condition beforerunning the second (or third…) participant in that condition. This procedure ensures thatany effects of time (experimenter or equipment fatigue, major historical events) would bedistributed fairly evenly over the conditions of the experiment.counterbalancingIn a repeated measures experiment, you would run participants in different orders.Depending on the number of levels of your factor, you might use complete or incompletecounterbalancing. With orders ≤ 5 you should use complete counterbalancing, which (withk orders) would require k! orders. With orders ≥ 5 you should use incompletecounterbalancing, which would require k orders if k is even and 2k orders if k is odd.reliabilityOne has a reliable instrument when one achieves the same measure on multipleapplications of the instrument to the same object. So, for instance, if one is measuring anindividual’s IQ, a reliable measure of IQ would be one that returned the same score everytime the test was administered. Reliability is important for experimental design because anunreliable dependent variable, for instance, will lead to an inflated error term.2. Dr. Sally Forth is interested in studying the relationship between Locus of Control (a measure developed by Dr.Julian Rotter) and the number of different people that a person has dated. She hypothesized that there would be apositive linear relationship between locus of control and the variety of a person’s dating partners (higher locus ofcontrol leading to greater number of different people dated). Dr. Forth collected data from 50 college students on herscale of Locus of Control (0 = Low and 10 = High). Interpret her results (seen below) as completely as you can.If a person had a Locus of Control score of 7, what would be your best estimate of the number of different peoplethat person would have dated? Be very explicit in telling me why you would not be willing to accept the conclusionthat one’s Locus of Control affected the number of different people one would have dated. [10 pts]500.669.448.4363.957CountNum. MissingRR SquaredAdjusted R SquaredRMS ResidualRegression SummaryNumber of Dates vs. Locus of Control1 609.318 609.318 38.918 <.000148 751.502 15.65649 1360.820DF Sum of Squares Mean Square F-Value P-ValueRegressionResidualTotalANOVA TableNumber of Dates vs. Locus of Control.285 1.205 .285 .237 .81381.228 .197 .669 6.238 <.0001Coefficient Std. Error Std. Coeff. t-Value P-ValueInterceptLocus of ControlRegression CoefficientsNumber of Dates vs. Locus of Control05101520253035Number of Dates0 1 2 3 4 5 6 7 8 9 10 11Locus of ControlY = .285 + 1.228 * X; R^2 = .448Regression PlotFirst of all, there is a positive linear relationship between Locus of Control and Number ofDates, such that people with higher Locus of Control tend to have had more dates thanpeople with low Locus of Control, r(48) = .669, p < .001. The coefficient of determination(r2) is .448, indicating that the two variables share a fair amount of variability. If a personhad a Locus of Control score of 7, one would predict that the number of dates would be8.88 (~9). Given the correlational design, one would not want to make a causal claim. Itcould very well be that one’s Locus of Control is affected by the number of dates one hashad (Causal Arrow problem). It may also be that some third variable, such as self esteem,may well produce the level of Locus of Control and the number of dates.3. Dr. Nomar Gassé was interested in the impact of varying levels of depression on a person’s ability to workeffectively on a task, especially when tired. He selected people who were not clinically depressed, but who receivedhigh scores on the Beck Depression Inventory, as well as people who were diagnosed as clinically depressed andseparated them into three groups (Low, Moderate, and Severe Depression). He then kept all participants awake for48 hours. At the end of the 48-hour period, each participant was given a set of 10 problems to solve. The DV wasthe number of problems solved correctly in a 30-minute period. Complete the source table below and interpret theresults of this study as completely as you can. [15 pts]2 221.911 110.956 131.891 <.0001 263.781 1.00042 35.333 .841DF Sum of Squares Mean Square F-Value P-Value Lambda PowerDepressionResidualANOVA Table for Prob Solved15 6.600 .986 .25415 3.333 .976 .25215 1.200 .775 .200Count Mean Std. Dev. Std. Err.LowModerateSevereMeans Table for Prob SolvedEffect: DepressionThere is a significant effect of depression on number of problems solved, F(2,42) = 131.89,MSE = .841, p < .001. Note, however, that level of depression is a nonmanipulatedcharacteristic of the participant, so one would not be able to make causal claims from thisstudy. In order to determine which groups differ, one would need to compute a post hoctest. HSD = 3.44.84115= .81Thus, we could conclude that people with low levels of depression solved significantly moreproblems than people with moderate or severe levels of depression. People with moderatelevels of depression solved significantly more problems than people with severe depression.4. In Mook’s article, he makes an argument about the value of experimental research that is not externally valid. Forthree of the following studies, indicate why the research is not externally valid and then tell me why they are stilluseful studies. [10 pts]Need to provide solid answers to these questions using Mook notes.Argyle study (glasses and intelligence)Hecht study (dark adaptation)Higgins & Marlatt study (anxiety and alcohol consumption)Brown & Hanlon (parental role in children's acquisition of grammatical speech)5. In