Testluv wrote:

nikit wrote:Can anyone please explain how 'C' can conclusively be inferred as the most appropriate option?

More and more kids are coming to the nurses office. The author argues that this can only be explained by greater exposure or greater sensitivity. So, he must be assuming that there aren't any other explanations.

Choice C clearly defends the argument against an alternative explanation. Use the Kaplan denial test:

If kids ARE more likely to be sent to the nurses office than before, then it is not necessarily the case that there is more exposure or more sensitivity.

Choice A is tempting because it also seems to defend the argument against an alternative explanation; after all, if there are fewer nurses, then each nurse would naturally be seeing more kids. However, the key is that "Elementary school nurses in Renston" are a group. And as a group they are reporting an increase in kids sent to them for these allergic reactions.

aspirant2011 wrote:Exposure to certain chemicals commonly used in elementary schools as cleaners or pesticides causes allergic reactions in some children. Elementary school nurses in Renston report that the proportion of schoolchildren sent to them for treatment of allergic reactions to those chemicals has increased significantly over the past ten years. Therefore, either Renston's schoolchildren have been exposed to greater quantities of the chemicals, or they are more sensitive to them than schoolchildren were ten years ago.

Which of the following is an assumption on which the argument depends?

A. The number of school nurses employed by Renston's elementary schools has not decreased over the past ten years.
B. Children who are allergic to the chemicals are no more likely than other children to have allergies to other substances.
C. Children who have allergic reactions to the chemicals are not more likely to be sent to a school nurse now than they were ten years ago.
D. The chemicals are not commonly used as cleaners or pesticides in houses and apartment buildings in Renston.
E. Children attending elementary school do not make up a larger proportion of Renston's population now than they did ten years ago.

ziyuenlau wrote:

aspirant2011 wrote:Exposure to certain chemicals commonly used in elementary schools as cleaners or pesticides causes allergic reactions in some children. Elementary school nurses in Renston report that the proportion of schoolchildren sent to them for treatment of allergic reactions to those chemicals has increased significantly over the past ten years. Therefore, either Renston's schoolchildren have been exposed to greater quantities of the chemicals, or they are more sensitive to them than schoolchildren were ten years ago.

Which of the following is an assumption on which the argument depends?

A. The number of school nurses employed by Renston's elementary schools has not decreased over the past ten years.
B. Children who are allergic to the chemicals are no more likely than other children to have allergies to other substances.
C. Children who have allergic reactions to the chemicals are not more likely to be sent to a school nurse now than they were ten years ago.
D. The chemicals are not commonly used as cleaners or pesticides in houses and apartment buildings in Renston.
E. Children attending elementary school do not make up a larger proportion of Renston's population now than they did ten years ago.

CONCLUSION : Therefore, EITHER Renston's schoolchildren have been exposed to greater quantities of the chemicals, OR they are more sensitive to them than schoolchildren were ten years ago.

(C) Children who have allergic reactions to the chemicals are NOT MORE LIKELY to be sent to a school nurse now THAN they were ten years ago.

Upon negating the answer choice (C), I found out that (C) does NOT weaken the conclusion but instead similar to the author's conclusion. Could someone help to elaborate in details?