Chapter 7, Problem AP2.22CPT

(a)

To determine

To Explain: that this is an observational study or an experiment.

Answer to Problem AP2.22CPT

Observational study

Explanation of Solution

An experiment deliberately forces some treatment on individuals in arrangement to detect their responses. An observational study tries to store information without disturbing the scene they are noticing. The subjects were not given any treatment due to the data being based on health records and therefore the researchers had no control over who took and who did not take omega-3 fish oil. If the no treatment was assigned, the study is an observational study.

(b)

To determine

To Explain: the concept of confounding in the context of this study and give one example of a variable that could be confounded with whether or not people take omega-3 fish oil.

Answer to Problem AP2.22CPT

Two variables are confounded if their affect on a response variable cannot be discriminated from each other. The amount of exercise is a possible confounding variable.

Explanation of Solution

Two variables are confounded when their affected on a response variable cannot be discriminated from each other. People who take omega-3 fish oil may be more interested in having a good health and therefore these people may exercise more. Although, the amount of exercise also affects of the amount of exercise is confounded with the omega-3 fish oil.

(c)

To determine

To find: the conclusion that omega-3 fish oil is the cause.

Answer to Problem AP2.22CPT

No, because there are possible confounding variables

Explanation of Solution

The conclusion from the previous part is that the study would be an observational study and that the study had possible confounding variables. As long as there are possible confounding variables which cannot be 100% assure that the omega-3 fish oil is the reason of the statistically significant difference.