A health professional is interested in finding out whether omega-fish oil can help lower cholesterol in adults. He gets permission to examine the health records of people at a large medical clinic and classifies them according to whether or not they are taking omega fish oil. She also obtained their most recent cholesterol readings and found that the mean cholesterol of those consuming omega-fish oil was a point lower than the mean of the group not consuming omega-fish oil.
Table of Contents
(a) Is this an observational study or an experiment? Explain. (b) Do these results provide conclusive evidence that omega-fish oil consumption lowers cholesterol? (c) Explain the term confounding in the context of this study and give one example of a possible confounding variable.
(a) The study is observational.
(b) The results do not provide conclusive evidence that omega-fish oil consumption lowers cholesterol.
(c) Two variables are confounded when their effect on the response variable cannot be distinguished. One example of a possible confounding variable is amount of exercise.
Part (a) Step 1: Providing information
Health records of people in a large medical clinic and classification according to whether or not they take omega-fish oil. To explain an observational study or experiment.
Part (a) Step 2: Explanation
In the given data, the experiment gradually sets some treatments on people to observe their returns. Observational analysis attempts to collect data without disturbing the scene.
People were not assigned any treatment because the information is based on medical records and the researchers did not include any control over who took the omega-fish oil and who did not. Because no treatment was given.
The study is therefore observational.
Part (b) Step 1: Providing information
The average cholesterol value of those consuming omega-fish oil is points lower than the average of the group that did not consume omega-fish oil. To explain these results, provide evidence that taking omega-fish oil lowers cholesterol.
Part (b) Step 2: Explanation
A medical doctor is experimenting to see whether or not omega-fish oil can help lower cholesterol in adults. As no treatment was assigned, the study is observational.
Because there are potential confounding variables, we cannot be sure that omega-fish oil is the cause of a statistically significant difference, which may be other factors influencing the outcome.
Thus, these results do not provide conclusive evidence that omega-fish oil consumption lowers cholesterol.
Part (c) Step 1: Providing information
Explain the term confounding in the context of the study and give one example of a possible confounding variable.
Part (c) Step 2: Explanation
In this study, two variables are confounded when their effects on the response variable cannot be distinguished from each other. People who take omega-fish oil may be more curious about maintaining good health, and these people may exercise more.
The amount of exercise also affects our cholesterol levels and fails to distinguish the effects of the amount of exercise from omega-fish oil, suggesting that some of the exercise is being confused with omega-3 fish oil. So, two variables are confounded. when their effects on the response variable cannot be distinguished from each other.
One example of a possible confounding variable is amount of exercise.
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