#8 - Doctor: In three separate studies, researchers compared

[valentina07]

Hi, I have the same questions as reop6780 mentioned above.

Overall, how is E is wrong?

[Jeff Wren]

Hi valentina,

Answer E tells us that out of 100 children, several of those children who had slept with night-lights as infants were nearsighted. Are these results good, bad, or do we have any idea? The fact that several of these children are nearsighted tells us nothing in and of itself. Perhaps several the children who didn't sleep with night-lights as children are also nearsighted; we don't know based on this information.

The important thing to understand is that the argument is not claiming that night-lights are the only cause of nearsightedness, so the fact that a few of the kids who had slept with night-lights are nearsighted really tells us nothing by itself; it could be complete coincidence.

What would be needed for Answer E to weaken the argument would be to show a properly conducted study in which a statistically meaningful difference was found between older children who had slept with night-lights being more likely to be nearsighted than those who did not.

Answer D, on the other hand, attacks the very studies that the argument relies on to draw its conclusion that the effect disappears with age.

[Mo28_28]

Hi,
I have read all the responses on this post but I'm not still convinced about D. Here is my thoughts on this:
In this argument we are going to say that there is probably some causal relationship between sleeping with night-lights as infants and being nearsighted to some age which was proven by the last study. On the other hand the argument suggests the first and the second study showing no correlation. Our task is to weaken the first and the second and by itself strengthen the third study.
In the argument, we are not presented with any number of children who were examined not in the first nor second and third. Going into answer choice D, it states the number in the first and second studies were not enough which is odd, because we can't argue something that there is no written clue about it ( words like some).
I think it's a better idea going with the disappearance with age, which is presented in answer choice E.
I look forward to hearing from you

[Mo28_28]

Hi,
I have read all the responses on this post but I'm not still convinced about D. Here is my thoughts on this:
In this argument we are going to say that there is probably some causal relationship between sleeping with night-lights as infants and being nearsighted to some age which was proven by the last study. On the other hand the argument suggests the first and the second study showing no correlation. Our task is to weaken the first and the second and by itself strengthen the third study.
In the argument, we are not presented with any number of children who were examined not in the first nor second and third. Going into answer choice D, it states the number in the first and second studies were not enough which is odd, because we can't argue something that there is no written clue about it ( words like some).
I think it's a better idea going with the disappearance with age, which is presented in answer choice E.
I look forward to hearing from you

I'm sorry. I made a mistake. In answer choice D, we are going to strengthen the first study and weaken the second and third.

[Jeff Wren]

Hi Mo,

First, when weakening an argument, you want to focus on the conclusion of the argument. Here we want to weaken the claim that "if nightlights cause near-sightedness, then the effect disappears with age." Because the conclusion is a conditional statement, we want to attack the necessary condition. In other words, we want to attack the idea that the effect disappears with age.

Since the claim that "the effect disappears with age" specifically relies on the second two studies of older students which found no correlation between night-lights and near-sightedness, an answer that attacks those studies will weaken this argument.

It is important to realize that we accept each answer choice as true for weaken questions (in fact the question directly asks which answer "if true" most weakens the argument).

You wrote "Going into answer choice D, it states the number in the first and second studies were not enough which is odd, because we can't argue something that there is no written clue about it ( words like some)."

This is incorrect. Weaken answers certainly can and often do bring up negative information that wasn't mentioned in the stimulus. You must analyze each answer to determine, if that answer were true, what impact would it have on the argument. If it weakens the argument, as Answer D would, then it is the correct answer.