magooshtravis wrote:
Okay, I understand your question better now. I think the explanation lies in the use of "many" and "most" in the problem.
The conclusion is that chess skills likely contribute to academic achievement. For something to be likely, it needs to be true more than half the time.
Now, the conclusion is based on the evidence claiming that most (more than half) of the chess kids got better in school. Answer choice C, however, implies that many of the chess kids improved in school for a reason other than chess. If you subtract "many" from "most," there is a chance that it's no longer true that more than half of the kids improved in school because of chess. Therefore, choice C calls into question the likelihood of the conclusion more than any other answer choice, and that's all it needs to do.
Remember, the question doesn't ask which answer destroys the conclusion. It asks which one "most tends to undermine" it.
i guess i understand that we are trying to find a choice that weakens the argument even by a tiny bit, as only one choice would weaken the argument to any extent, and the rest four would either be neutral or strengthen the arg. even though instructions ask to pick the one that most weakens, i think it's supposed to protect lsac in case of question disputes and the test is designed so that no question will have two choices that weaken to different degrees and a choice stands on its own merit. so in your answer, it seems you suggest that choice1 would not weaken but choice2 would, even though "some" and "many" have similar logical force as both suggest anything greater than none but neither of them suggest "most". since they have same logical force, i am not sure how it could be uncontroversial that choice-1 doesn't weaken but choice-2 does?
conclusion: most A are B (or "A is likely B")
choice-1: some A are ~B
choice-2: many A are ~B
christine defenbaugh of mlsat had posted thoughts about this issue regarding another question a while ago. she seems to hold that for a "some/many" choice can't weaken a "most" conclusion shown above, but it
can weaken a definitive conclusion. so if the conclusion were: "all A are B (or "A is B")" then both choices weaken it, but neither does when the conclusion is not definitive and just likely.
Christine (MLSAT) wrote:
To sum up: For a 'some' statement to be relevant, a number of things have to be true - the conclusion is going to be definitive (the assumption is extreme - more vulnerable to attack and receptive to support); the one of the elements in the 'some' statement needs to match the information from the premise; we need to not ALREADY have the essential 'some' information in the premises.
here is the quote, but you can look up the details at
http://www.top-law-schools.com/forums/v ... 8#p8600218
magooshtravis wrote:
B) Irrelevant--the argument is about students who finished the program. Furthermore, the preprogram levels of achievement of a student are only relevant to the same student's postprogram levels. We are not comparing students to each other.
the argument is about students who finished the program but B also tells us something about those same students, which is that they had a
higher pre-program level of achievement than those who didn't complete. it does seem to
compare these students as being better than others who eventually didn't finish even before the program began. this strongly suggests that they were better intellect students even prior to beginning the program compared to other students. therefore it provides alternate reason that their increase in achievement could be due to them being innately better and not due to chess?
