December 2014 SEC 4 Q18

Hi @kenken, Happy to help! Say the study was focused on people who took melatonin. A result of this study may be that taking melatonin can help to alleviate the symptoms of insomnia. Answer choice (A) would be correct if the pharmacist concluded that the group of people must have taken melatonin to alleviate the symptoms of insomnia. Just because taking melatonin has this effect does not mean that the people in the study took it for this reason. There are numerous other reasons why the study participants may have initially taken the melatonin; the alleviation of the symptoms of insomnia may just be an unintended side effect. Let us know if you have any further questions!