GMAT Critical Reasoning
Of the 60 participants in a clinical trial, 30 participants were considered to be in the experimental group, and were administered a large dose of an experimental painkiller called nexaphedrinol, while the 30 remaining participants were considered to be in the control group, and were administered the same dose of a placebo. Afterward, participants in the experimental group exhibited fine motor skills that were more diminished than those of the control group. The observed detrimental effects on fine motor skills were attributed to a compound in nexaphedrinol called phedrine, which temporarily damages nerve endings.
Which of the following, if true, would best support the conclusion that a certain compound in the painkiller was responsible for the observed results?
- A Nexaphedrinol has been found to be the most effective painkiller available in a variety of preceding experiments that utilized similar methodologies.
- B Phedrine is a relatively ubiquitous compound found in a variety of medicines, some of which may have been taken by the participants in the experiment.
- C The placebo administered to the participants in the experiment did not contain phedrine but may have contained a compound with similar effects on nerve endings.
- D All the participants in the experiment were found to have had comparable fine motor skills prior to the administration of the nexaphedrinol or the placebo.
- E Most customers suffering from chronic pain have indicated that they would be willing to suffer a decrease in fine motor skills in exchange for an effective painkiller.
Correct Answer: D