Chapter 7.2, Problem 52E

(a)

To determine

To Explain: that the confounding makes it difficult to establish a cause and effect relationship between whole grain consumption and risk of dying from heart disease, stroke, or caner, based on these studies.

Answer to Problem 52E

Amount of exercise could be confounded the results

Explanation of Solution

Two variables are confounded when their affects on a response variable cannot be discriminated from each other.

It cannot be established a cause-and −effect between whole grain consumption and risk of dying from heart disease, stroke, or cancer, the reason is that it is possible that the result of the study are confounded with another variable.

For example, the amount of exercise could influence the risk of dying from heart disease, stroke, or cancer, because if you exercise more, then you are healthier and thus you could then be less likely to suffer from dying from heart disease, stroke, or cancer. Although it cannot be discriminated the amount of exercise and whole grain consumption

(b)

To determine

To Explain: that the researcher could establish a cause and effect relationship in this context.

Explanation of Solution

It is possible to establish a cause- and-effect relationship in this context, if using an experiment instead of observational studies For example; it could use a completely randomized experiment. A completely randomized experiment randomly assigns all subjects to a group.

Select a group of people and randomly assign half of the group to the treatment group, where the remaining group is assigned to the control group.

The people in the treatment group eat 3 servings of whole grain per day, where the people in the control group do not eat whole grains at all.