Question

researchers conducted a study to determine whether magnets are effective in treating back pain. pain was measured using the visual analog scale, and the results given below are among the results obtained in 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}) = 0.487, s = 0.955 reduction in pain level after sham treatment: n = 20, (\bar{x}) = 0.439, s = 1.36 choose the correct answer below. a. the study is an experiment because subjects were given treatments. b. the study is an observational study because the subjects are a simple random sample. c. the study is an observational study because there was no attempt to modify the individuals being studied. d. the study is an experiment because the subjects are a systematic sample.

Explanation:

To determine if the study is an experiment or observational study, we recall the definitions:

• An experiment involves applying a treatment (or intervention) to subjects and observing the effect.
• An observational study involves observing subjects without modifying or intervening (e.g., no treatment is applied; we just observe existing conditions).

In this study, subjects were given two types of treatments: Magnet Treatment and Sham Treatment. Since treatments were administered (the researchers actively modified the subjects’ conditions by giving them different treatments), this is an experiment.

Now, let’s analyze the options:

• Option A: States it is an experiment because subjects were given treatments. This matches the definition of an experiment (administering treatments to test an effect).
• Option B: Claims it is an observational study because subjects are a simple random sample. But the type of sampling (simple random) does not determine if it’s experimental or observational—what matters is whether a treatment was applied. Eliminate B.
• Option C: Claims it is an observational study because there was no attempt to modify individuals. But the study did apply treatments (Magnet and Sham), so there was an attempt to modify (by giving treatments). Eliminate C.
• Option D: Claims it is an experiment because subjects are a systematic sample. The type of sampling (systematic) does not define an experiment—experimentation is about applying treatments, not the sampling method. Eliminate D.

Answer:

A. The study is an experiment because subjects were given treatments.