Question

A student has been asked to design an ethical study to better understand whether a diet high in saturated fats increases risk of heart disease. The student must a) state the hypothesis, b) state the rationale behind the hypothesis, and c) describe a high-quality observational study that addresses the hypothesis. The student’s answer is below. Identify all problems with the student’s answer and discuss how they could be corrected. a) Hypothesis: Do saturated fats increase the risk of heart disease? b) Rationale: I believe saturated fats will increase the risk of heart disease. Saturated fats have more fatty acids attached to glycerol than do unsaturated fats, and that makes them get stuck in blood vessels. c) Study design: I will go to a hospital and find 100 patients that are diagnosed with heart disease. I will then go to a gym and find 100 people that do not have heart disease. I will ask all 200 subjects to fill out a diet questionnaire to determine how much saturated fat they eat. My independent variable is saturated fat and my dependent variable is whether they have heart disease. If the patients with heart disease have diets higher in saturated fats than those patients without heart disease, then I can conclude that saturated fats cause heart disease.

Answer 1

The student's hypothesis should be a declarative statement, the rationale should be scientifically backed, and the study design requires a randomized population sample and must account for confounding variables to accurately assess the relationship between saturated fats and heart disease.

Step-by-step explanation:

The student's proposed study has several methodological issues that must be addressed. First, the hypothesis should be a statement, not a question. It could be framed as: 'A diet high in saturated fats increases the risk of heart disease.' Second, the rationale should be backed up by existing scientific research and biological mechanisms, not by a belief. A more factual rationale could include information on how saturated fats contribute to atherosclerosis or other forms of heart disease.

The suggested observational study design is flawed in its selection of subjects and would not adequately address the hypothesis. Patients in hospitals may have many confounding variables influencing their heart disease; likewise, individuals in gyms might have different lifestyle factors affecting their health. A more robust study would need a randomized sample from the general population. Furthermore, simply establishing a correlation between diets high in saturated fats and heart disease does not imply causation. To improve the study, the student should account for potential confounding factors such as age, gender, physical activity levels, and other dietary habits.