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Chapter 2: Problem 43

Swedish researchers concluded that viewing and discussing art soothes the soul and helps relieve medical conditions such as high blood pressure and constipation (AFP International News Agency, October 14,2005 ). This conclusion was based on a study in which 20 elderly women gathered once a week to discuss different works of art. The study also included a control group of 20 elderly women who met once a week to discuss their hobbies and interests. At the end of 4 months, the art discussion group was found to have a more positive attitude, to have lower blood pressure, and to use fewer laxatives than the control group. a. Why would it be important to determine if the researchers assigned the women participating in the study at random to one of the two groups? b. Explain why you think that the researchers included a control group in this study.

Short Answer

Expert verified
Random assignment ensures the initial equivalence of groups, preventing bias and allowing for a valid comparison between groups. Hence, any observed differences can be attributed to the different treatments (art or hobby discussion) rather than pre-existing differences. Researchers included a control group to isolate the effects of the ‘treatment’, in this case, discussions about art. This allows for a comparison between groups to evaluate the influence of the 'treatment'.

Step by step solution

01

Understand the importance of random assignment

Random assignment in research minimizes the effects of confounding variables and bias, making sure the groups are equivalent at the beginning of the study. This promotes the validity of the conclusion, as any difference between the groups can be attributed to the treatment (in this case, the art discussion), rather than any pre-existing differences between individuals or groups.
02

Explain the inclusion of the control group

A control group in a study is essential to isolate the effect of the treatment. By including a control group that does not receive the treatment (in this case, the art discussion), any changes observed in the art group can be interpreted as the effect of the treatment, removing the impact of possible external factors. The control group in this study (those who discussed hobbies) serves to determine the normal outcome of not having the 'treatment', hence providing a base for comparison.

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