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A pharmaceutical company has developed a new medicine for compulsive behavior. To test this medicine on humans, the physicians conducting this study obtained a list of all patients suffering from compulsive behavior who were being treated by doctors in all hospitals in the country. Assume that this list is representative of the population of all such patients. The physicians then randomly selected 1820 patients from this list. Of these 1820 patients, randomly selected 910 patients were assigned to the treatment group, and the remaining 910 patients were assigned to the control group. Neither patients nor doctors knew what group the patients belonged to. Six months later the conditions of the patients in the two groups were examined and compared. Based on this comparison, the physicians concluded that this medicine improves the condition of patients suffering from compulsive behavior. a. Is this an observational study or a designed experiment? Explain. b. Is this a double-blind study? Explain.

Step by step solution

01

Identify The Type of The Study

The researchers have assigned treatments or actions to the subjects, the group of patients, and then observed their responses in the experimental group as compared to the control group. This characteristic is fundamentally present in designed experiments, where the experimenters assign treatment to subjects rather than observing them in their natural environment without intervention. Therefore, this is a designed experiment.

02

Determine if the Study is Double-Blind

In a double-blind experiment, neither the participants nor the experimenters know who is receiving a particular treatment. This condition is designed to prevent bias in research results. In this case, it is mentioned that neither the participants (patients) nor the experimenters (doctors) knew what group the patients belong to. Therefore, this is a double-blind study.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Double-Blind Study

In the realm of scientific research, a double-blind study is a powerful tool used to eliminate bias. This setup ensures that both the participants and the researchers do not know which participants are receiving the treatment and which are receiving a placebo or standard treatment. This approach helps ensure that the results are not influenced by the expectations of the participants or researchers.

In the context of the study described, the pharmaceutical company's experiment was conducted in a double-blind fashion. Both the patients and the doctors were unaware of the group assignments. This prevents any preconceived ideas from affecting the outcomes of the study, leading to more reliable and valid results.

Eliminating bias is crucial in clinical trials, as it provides a cleaner comparison between the treatment group and control group outcomes. Utilizing a double-blind study methodology is a gold standard in research design, enhancing the credibility of the study findings.

Treatment Group

In any controlled experiment, participants are divided into different groups. One such group is the treatment group. This term refers to the group of participants that receives the experimental treatment or intervention. For the study in question, the treatment group consisted of 910 patients.

This group was given the new medicine for compulsive behavior developed by the pharmaceutical company. Often, the treatment group's outcomes are compared against those of the control group to measure the effectiveness of the treatment.

Key points about treatment groups:

• They receive the actual treatment or intervention being tested.
• Their results are crucial in gauging the treatment's impact, generally compared against the control group.
• Understanding the results from the treatment group allows researchers to conclude whether the intervention has a significant effect.

Control Group

Opposite to the treatment group, the control group is composed of participants who do not receive the experimental treatment. Instead, they may receive a placebo or no treatment at all. This group serves as a benchmark to measure how the treatment group performs relative to normal or expected outcomes without the intervention.

In this study, another set of 910 patients was placed in the control group. By comparing the changes between the two groups, researchers can identify the actual effect of the medicine.

Important aspects of control groups:

• They help in creating a baseline to compare the treatment group's results against.
• Control groups are essential for validating the findings of a study.
• They allow for a clearer understanding of the treatment's efficacy by showing what happens without the intervention.

Random Selection

Random selection is a core component of rigorous scientific studies. It involves selecting participants randomly from the population to ensure that each individual has an equal chance of being included in the sample. This process helps create a study sample that is representative of the larger population.

In the context of this study on compulsive behavior, 1820 patients were randomly selected from a comprehensive list of patients. This random selection ensures that the group of patients in the study is diverse and representative, helping to generalize the findings to the entire population of interest.

Advantages of random selection:

• It minimizes selection bias, contributing to the reliability of the study results.
• It ensures the sample's diversity, making findings more applicable to the broader population.
• Random selection supports the internal and external validity of the research outcomes.