Exam 8: Complex Designs

There are several steps an investigator must take in carrying out the general procedure for drawing causal inferences based on the natural groups design.Which of the following is not one of the steps an investigator must take?

Assume the following results were observed for the mean Verbal scores (we'll ignore quantitative scores): Based on these findings,the researcher claims that Test Version,computer vs.paper,does not affect individuals' average performance.What data is the researcher using to make this claim? Is this claim justified?

A researcher designs a 2 × 2 × 2 complex design in which the first independent variable uses a random groups design,the second independent variable uses a natural groups design,and the third independent variable uses a repeated measures design.The researcher wants to have 20 participants in each independent groups condition.How many participants will she need to recruit?

A researcher conducts a study to determine if the variable of test anxiety influences performance on the GRE verbal and quantitative tests. He uses a questionnaire to assess individuals' test anxiety and classifies participants as high test anxious (n = 20) or low test anxious (n = 20). He is also interested in knowing whether high or low test-anxious individuals' performance is different for the computerized version of the test compared to the paper-and-pencil version of the test. Within each anxiety group, he randomly assigns participants to either the computer version or the paper version of the GRE tests. Participants then complete both the verbal and quantitative tests of the GRE in the test version they've been assigned (computer or paper). -What is the manipulated independent groups variable in this study? What are the levels?

The analysis plan and interpretation of the results of a complex design experiment involving two independent variables depends on

Figure: A researcher was interested in the effects of arousal and personality on individuals' GRE test performance.The personality variable he examined was individuals' level of introversion-extraversion.Based on questionnaire responses,each participant was classified as an "extravert" or an "introvert." The researcher manipulated arousal level by giving caffeine to participants prior to administering a practice GRE test.Participants were randomly assigned to a high-caffeine condition,a medium-caffeine condition,or the no-caffeine conditions.All participants then completed a practice version of the quantitative portion of the GRE. Suppose the researcher observed the following means for each group: -The natural groups independent variable in this experiment is

Explain the role of an interaction effect in a complex design in establishing the external validity of each independent variable entering into the interaction effect.Be sure to describe what happens to external validity both when an interaction effect is and is not present.Finally,explain why you might be cautious in using interaction effects to establish the external validity of the effect of an independent variable.

A common approach for resolving contradictory findings in research literature is to develop a theory for the source of different findings and

The overall effect of each independent variable in a complex design is called a(n)

Complex designs enhance researchers' ability to test hypotheses derived from theories because complex designs

Figure: A researcher examined whether interrogators who expect a suspect to be guilty,rather than innocent,use more persuasive interrogation techniques.The researcher created a laboratory situation in which students (the "suspects")were randomly assigned to actually commit a crime or not commit a crime by following a set of instructions given to them.Student interrogators then interviewed a suspect;they were randomly assigned to conditions that led them to believe the suspect was guilty or innocent of the crime.Observers rated the effort used by interrogators to obtain a confession using a 1-10 rating scale (higher scores indicate greater effort). Suppose the researcher observed the following means for each group: -Assuming any nonzero difference is statistically significant,these results would most likely indicate a

Which of the following patterns indicates that there has been no interaction effect in a complex design experiment when the results are plotted in a line graph?

In a complex design experiment researchers found that younger and older people performed equally well on a memory task when they were tested in the morning,but the younger people performed better than the older people when they were tested in the afternoon.The different effect of age at the two times of day represents a(n)

Complex designs beyond the basic 2 × 2 design can be constructed

The following table includes the results of a 2 × 2 design in which one independent variable was the gender of a research confederate leading a group discussion (male or female)and the second independent variable was the outcome of the group performance (success or failure).Both variables were manipulated by the experimenter using random groups designs.The dependent variable was participants' rating of the confederate leading the discussion.There is an interaction effect in this experiment.Which of the following statements is appropriate for describing the interaction effect?