Chapter 8.1, Problem 25E

(a)

To determine

Check whether the survey is an observational study or an experiment.

Answer to Problem 25E

This survey is an observational study.

Explanation of Solution

An experiment procedure for some treatment on individuals in order to observe the possible outcomes, which cannot be predicted with certainty.

In observational study,researcher simplygather information from any sample without disturbing the sample. Observational study can be done after an experiment.

Since, the researchers collect all data.

Hence, this survey is an observational study.

(b)

To determine

Explain whether the study proves that living near power lines doesn’t cause cancer.

Answer to Problem 25E

The observational study doesn’t show that living near power lines can cause cancer or not.

Explanation of Solution

An observational study simply gather data from any sample. Observational study doesn’t allow to control any variable that could affect the results of the study.

Hence, the observational study doesn’t show that living near power lines can cause cancer or not.