Researchers conducted a study to determine whether magnets are effective in treating back pain. Pain was measured using the visual analog scale, and the the study. Higher scores correspond to greater pain levels. Is this study an experiment or an observational study? Explain. Reduction in Pain Level After Magnet Treatment: \( n=20, \bar{x}=0.493, s=0.963 \) Reduction in Pain Level After Sham Treatment: \( n=20, \bar{x}=0.437, s=1.41 \) Choose the correct answer below. A. The study is an experiment because the subjects are a systematic sample. B. The study is an experiment because subjects were given treatments. C. The study is an observational study because the subjects are a simple random sample. D. The study is an observational study because there was no attempt to modify the individuals being studied.

The study described involves researchers assigning subjects to either a magnet treatment or a sham (placebo) treatment to observe the effects on back pain levels. This assignment and manipulation of treatment are key characteristics of an **experiment** rather than an observational study. - **Experiments** involve the researcher actively intervening by assigning treatments to different groups and then measuring the outcomes. - **Observational studies** involve observing subjects without any intervention or treatment assignment by the researcher. In this case, since the researchers **gave treatments** (magnet or sham) to the subjects, they are actively modifying the conditions to study the effect, which categorizes the study as an experiment. **Correct Answer:** **B. The study is an experiment because subjects were given treatments.**