Many scientific studies have suggested

Answer choices

1. A

   Too Weak / Unclear Impact23% picked this

   A weaker correlation between taking melatonin and the inducement of sleep was found in the studies that included people with insomnia than

   This is worth keeping at first, but it is not as impactful as C. The author leaves us wondering about the studies that did include insomniacs. This answer seems to help us believe the conclusion, because the data from the insomniac studies was even less compelling in terms of portraying melatonin as having any strong effect on inducing sleep. However, as soon as you add insomniacs (people who have a really hard time falling asleep) into a sleep study, the rate of people falling asleep is likely to go down compared to groups without insomniacs. That alone could explain the weaker correlation, whereas it might still be true that within this group, insomniacs who took the melatonin had an easier time sleeping than those who didn’t take it.

   23%
2. B

   Too Weak / Opposite Direction5% picked this

   None of the studies that suggested that taking melatonin tablets can induce sleep examined a fully representative sample

   This would weaken more than anything. Finding out studies were not representative makes us less likely to rely on them as evidence. Saying they were not fully representative is a very mild knock on them, but it’s still a detriment, not a strengthener.

   5%
3. C

   Correct60% picked this

   In the studies that included subjects with insomnia, only subjects without insomnia were significantly affected

   Why this is right

   This does what A is drifting towards, but this explicitly tells us about the insomniac data points in the study – they were not significantly affected by melatonin. The info in A is not as clear in that regard, as it provides a statement about the entire data set in the studies that had insomniacs, not specific data about the insomniacs.

   Skill tested: Strengthen · how this choice captures the argument's function is the move to repeat next time.

   60%
4. D

   Too Weak / Unclear Impact4% picked this

   Several people who were in control groups and only given placebos claimed that the

   This is weakly worded, as it’s only about a handful of people, so it’s very unlikely to be correct. This handful of people benefited from the placebo effect, not the melatonin. But this doesn’t address our central questions: what about the studies that included insomniacs? Were any of the people who were actually given melatonin and appeared to be affected by it insomniacs?

   4%
5. E

   Unclear Impact9% picked this

   If melatonin were helpful in treating insomnia, then every person with insomnia who took doses of melatonin would appear to

   This is a very strong idea, which is desirable. The contrapositive says, “If you’re an insomniac who took melatonin and did not appear to be significantly affected by it, then melatonin is not helpful in treating insomnia.” This rule is perfectly designed to get us to our conclusion. Can we trigger this rule from what we know from the Evidence? Did the author provide examples of insomniacs who were given melatonin but did not seem significantly affected by it? She did not. Her evidence is unclear in regards to whether any insomniacs who took melatonin were or were not affected by it. Since we can’t trigger this conditional, this rule has no impact on our evaluation of the argument.

   9%