Indicate Whether Each Of The Following Studies Is An Experim

Indicate Whether Each Of The Following Studies Is An Experiment Or

1. An investigator wishes to test whether, when compared with recognized scientists, recognized artists tend to be born under different astrological signs.

2. To determine whether there is a relationship between the sexual codes of primitive tribes and their behavior toward neighboring tribes, an anthropologist consults available records, classifying each tribe on the basis of its sexual codes (permissive or repressive) and its behavior toward neighboring tribes (friendly or hostile).

3. A school psychologist wishes to determine whether reading comprehension scores are related to the number of months of formal education, as reported on school transcripts, for a group of 12-year-old migrant children.

4. A social scientist wishes to determine whether there is a relationship between the attractiveness scores (on a 100-point scale) assigned to college students by a panel of peers and their scores on a paper-and-pencil test of anxiety.

5. A psychologist uses chimpanzees to test the notion that more crowded living conditions trigger aggressive behavior. Chimps are placed, according to an impartial assignment rule, in cages with either one, several, or many other chimps. Subsequently, during a standard observation period, each chimp is assigned a score based on its aggressive behavior toward a chimplike stuffed doll.

6. A researcher allows college students to choose to participate in either a GRE test-taking workshop or a control (non-test-taking) workshop and then compares the GRE scores earned subsequently by the two groups of students.

7. Investigators found that four-year-old children who delayed eating one marshmallow in order to eat two marshmallows later scored higher than non-delayers on the Scholastic Aptitude Test (SAT) taken over a decade later.

8. A political scientist wishes to determine whether males and females differ with respect to their attitudes toward defense spending by the federal government. She asks each person if he or she thinks that the current level of defense spending should be increased, remain the same, or be decreased.

9. In a study of group problem solving, an investigator assigns college students to groups of two, three, or four students and measures the amount of time required by each group to solve a complex puzzle.

Paper For Above instruction

Understanding the distinction between experimental and observational studies is fundamental in research methodology, as it impacts the interpretation of causal relationships and the validity of inferences drawn from data. Experiments involve the deliberate manipulation of an independent variable to observe its effect on a dependent variable, often with random assignment to control for confounding factors. Observational studies, on the other hand, involve observing and measuring variables without manipulation, with researchers analyzing existing conditions or behaviors.

Among the listed studies, several are experiments. For example, the study with chimpanzees testing the effect of crowding on aggressive behavior clearly involves manipulation of the living conditions—the independent variable being the crowding level (number of chimps per cage). The researcher randomly assigns chimps to different cages, which qualifies it as an experiment. Confounding variables could include individual temperament or prior social experiences. Including control for these factors strengthens the study's internal validity. The study involving group problem solving also exemplifies an experiment; the independent variable is group size, manipulated by assigning students to groups of specific sizes. Measurement of problem-solving time examines the dependent variable, while confounding variables might include individual abilities or prior experience with puzzles.

The study examining the relationship between reading comprehension and months of education is observational, as it involves analyzing existing data without manipulation. Similarly, the research on attractiveness scores and anxiety as well as the research on attitudes towards defense spending are observational, establishing correlations without experimental control.

Studies involving self-selection, such as the one where students choose whether to attend a GRE workshop, are observational because the researcher does not assign students to groups; instead, participants self-select into conditions, which introduces potential selection bias. This bias complicates causal inferences because differences in scores could result from pre-existing differences rather than the workshop itself.

The study on marshmallow delay and SAT scores. This is observational too, as the children’s initial delay was not manipulated by the researcher but observed as a natural behavior, and their later SAT scores are measured as outcomes. While it provides interesting longitudinal data, it cannot definitively establish causality due to potential confounding factors like inherent self-control or intelligence.

The study on attitudes towards defense spending involves survey methodology, which is observational. Researchers record attitudes expressed naturally, rather than manipulating the variables.

In summary, the key criterion for classifying these studies as experiments or observational studies lies in whether the researcher manipulates the independent variable and uses random assignment (experiments) or simply observes and records natural variations without intervention (observational).

References

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