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# Exposure to certain chemicals commonly used in elementary schools

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Re: Exposure to certain chemicals commonly used in elementary schools [#permalink]

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09 Nov 2013, 02:58
IMO C:
Premise:Nurses have reported a increase in proportion of school children sent to them for treatment of allergic reactions over the past ten years.
conclusion: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.
Now the premise and conclusion would stand true if the number of children getting and reporting allergic reactions due to exposure to these chemicals has increased and not just number of children reporting allergic reactions has increased....
Only C satisfies this condition....
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Re: Exposure to certain chemicals commonly used in elementary schools [#permalink]

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05 Dec 2013, 13:53
D, is the only best option, if we negate option D, we will get a conclusion which will weak the "either option 1 or option 2" in conclusion as it will raise option 3, and in that case authors conclusion will become ineffective.
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Re: Exposure to certain chemicals commonly used in elementary schools [#permalink]

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16 Mar 2014, 22:57
I got wrong.. I chose option B..

In assumption question , when argument give few reasons or cause of something.. then in assumption question, usually we do say that no anything else is the cause of that effect..
i mean in this question,
, 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.

Two reasons have been given for proportion of children of elementry school have increased to elergy..
So i chose B because it says that there is no anyother substance that affect those children.

will anyone explain where m wrong?? experts?
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Re: Exposure to certain chemicals commonly used in elementary schools [#permalink]

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29 May 2014, 02:10
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amit2k9 wrote:
close call between A and C here.

Negating A means that as the number of nurses has decreased,even though the number of children sent remains the same,children seen/nurse has increased.

Negating C means it is more likely that children will be sent to the nurses now than earlier.

C seems closer to the conclusion here. The number of nurses hasn't been discussed in the stem.

Hence C preferred.

Also, the arguments suggests the nurses as group. The individuals within the set might increase or decrease. The number of children that has been sent to the group has increased.

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Re: Exposure to certain chemicals commonly used in elementary schools [#permalink]

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14 Aug 2014, 02:30
I understand why option C is correct but cannot figure out why option B is wrong.
If the children allergic to the chemicals are more likely to have allergies to other substances, the increase in proportion is, therefore, due to other reasons rather than the chemicals. The conclusion will be annulled that the schoolchildren are exposed to more "those chemicals" or they are more sensitive to "those chemicals".
I find few comments on the Internet discuss why option B is invalid and those that mention simply say that option B is irrelevant or out of scope.

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Re: Exposure to certain chemicals commonly used in elementary schools [#permalink]

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19 Sep 2014, 09:02
Two questions -

1. How do we assume what proportino the question stem is referring to? How can we assume its - students sent to nurses for allergic reaction to nurses/ total students (or total students sent to the nurses). How do we determine what the proportion is in between.

2. Option E - If there are more children in Renston attending elementary school, then they were 10 years ago, wouldn't that increase the number of students coming for allergic reaction. But yes, if we talk about proportion, we can negate that.

E. Children attending elementary school do not make up a larger proportion of Renston’s population now than they did ten years ago.
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Re: Exposure to certain chemicals commonly used in elementary schools [#permalink]

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25 Oct 2014, 05:07
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I read in most of the answer explanations that choice A is irrelevant. Choice A is wrong, but certainly not irrelevant, because if the number of nurses decrease and the number of children remain constant, then every nurse will be treating more children than he / she used to 10 years ago.

But this assumption assumes that the number of children have remain same / not decreased, thus the choice A holds wrong.
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Re: Exposure to certain chemicals commonly used in elementary schools [#permalink]

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25 Dec 2014, 05:40
sanjoo wrote:
I got wrong.. I chose option B..

In assumption question , when argument give few reasons or cause of something.. then in assumption question, usually we do say that no anything else is the cause of that effect..
i mean in this question,
, 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.

Two reasons have been given for proportion of children of elementry school have increased to elergy..
So i chose B because it says that there is no anyother substance that affect those children.

will anyone explain where m wrong?? experts?

Exactly. Just as you mentioned, an assumption that you can pull out of this argument is that there is NOTHING ELSE that can cause this significant increase of students getting sick and reporting to the nurse's office.

With Choice B: "Children who are allergic to the chemicals are no more likely than other children to have allergies to other substances."
The thing is, we're not even concerned with children who have "allergies to other substances."
The focus of the argument is on chemicals inside the school, alone. This choice flies Outside the Scope of our argument.

Choice C is exactly what we want. If we negate it, "Children who have allergic reactions to the chemicals ARE more likely to be sent to a school nurse now than they were ten years ago." --> gives us another reason why we have the "current" increase in sick students. This completely destroys the argument, and is the Slam Dunk link connecting our Premise to our Conclusion.

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Re: Exposure to certain chemicals commonly used in elementary schools [#permalink]

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26 Dec 2014, 04:30
If we try to negate the argument then lets see what happens---If not more children are sent now then 10 years ago then we can have another reason to have the percentage increase. Hence argument falls so C is the answer.

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Re: Exposure to certain chemicals commonly used in elementary schools [#permalink]

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30 Dec 2014, 09:26
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.

P1: Exposure to certain chemicals used as cleaners or pesticides===> allergic reactions to some
P2: Nurses have reported that the proportion of School children(out of all the children coming to them for treatment) has increased signifcantly.
P2 implies that nurses treat more number of schoolchildren with allergy complaints than number of non-school going children.

Conclusion: The school children are either exposed more to these chemicals or they(school children) are getting more sensitive, in case they are not exposed to greater amount of these chemicals.

Assumptions linking P2 to conclusion: more schoolchidren sent to nurses for allergy treatment than non-school going children
or there is less probability that children(broader term= school going children+non- school going children) to be sent to nurses for allergy treatment. this means there is greater possibility that they cater more to school children(because they are school nurses) than normal children. This assumption bolsters the nurses claim + it also strengthens the author's conclusion that they are exposed more an hence the visits of the school children to nurses have increased.

Now lets evaluate the answer choice:
A) The number of school nurses employed by Renston’s elementary schools has not decreased over the past ten years.
-talks about decrease in the number of nurses. This statement does give a idea that the proportion might have increased if there had been a decrease in number of nurses. Ruling out this probability seems a valid assumption, but this does not certifies the conclusion that children are being over sensitive or greatly exposed. So wrong.
B)Children who are allergic to the chemicals are no more likely than other children to have allergies to other substances.
-Allergies to other substances is definitely out of scope. so wrong.
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.
- Now had it been false, it would have implied that the nurses not only treat school children but other children as well. So in order to prove that premise 2(nurses claim) is true, there had been only one way and that would have been that the number of school children has increased or at least the case of their getting allergies has increased..which may have occurred because of little exposure yet to more people or greater sensitivity to same set of students or greater exposure as concluded by the author. Negating this statement does provide an extra cause to the effect which should not have happened for the conclusion to be true. so this is correct choice.
D) The chemicals are not commonly used as cleaners or pesticides in houses and apartment buildings in Renston.
- the use of chemicals at homes or other places is definitely out of scope
E) Children attending elementary school do not make up a larger proportion of Renston’s population now than they did ten years ago.
- This information is irrelevant to the argument. whether the children attending elementary school make a large proportion or a small proportion, won't stop the author from making the conclusion. Plus talking about city's population is out of scope.

But I do believe that instead of reasoning process of elimination would have been the best approach in this case. filtering out options that are not linking premises to conclusion. You can easily spot that most of the options are either out of scope or adrress only conclusion or only premise.

I am still learning concepts. So i would appreciate if i do get a critical review to my approach!
Suggestions are always welcome.

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Re: Exposure to certain chemicals commonly used in elementary schools [#permalink]

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21 Feb 2015, 05:06
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Took a lot of time to decide between C und E.
We have a sound argument here, so don't look for GAP in this case, we need a DEFENDER (see CR Bible) here, which eliminates a possible WEAKENER.

1) The argument says there are 2 possible reasons - a weakener could be a 3rd possible reason, which we eliminate.
2) Let's talk about proportions, relevant proportion here is a # of children sent with allergic reactions / # of school children

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 --> CORRECT. That could be our 3rd reason and is actually a good weakener. So sliminating this one would DEFEND our argument.

E. Children attending elementary school do not make up a larger proportion of Renston’s population now than they did ten years ago --> This one talks about the wrong proportion - so, it doen't weaken the argument. We need a proportion children with allergie / children and not children / population of the city.
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Last edited by BrainLab on 22 Feb 2015, 03:43, edited 1 time in total.

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Re: Exposure to certain chemicals commonly used in elementary schools [#permalink]

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21 Feb 2015, 12:26
sanjoo wrote:
I got wrong.. I chose option B..

In assumption question , when argument give few reasons or cause of something.. then in assumption question, usually we do say that no anything else is the cause of that effect..
i mean in this question,
, 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.

Two reasons have been given for proportion of children of elementry school have increased to elergy..
So i chose B because it says that there is no anyother substance that affect those children.

will anyone explain where m wrong?? experts?

I can see your confusion, but you have to be careful about the exact language in the question. This question is about "certain chemicals", but answer choice B is talking about chemical other than those "certain chemicals". It's what we would call "out of scope" of the argument because it's not talking about the same chemicals.

Your rationale about other causes is perfectly suited to C. It eliminates the possibility that people are just more likely to run to the nurse when experiencing a reaction.

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Re: Exposure to certain chemicals commonly used in elementary schools [#permalink]

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22 Feb 2015, 11:22
C basically eliminates alternate cause to reach the conclusion. A higher proportion of schoolchildren are being sent to nurses, for treatment of allergic reactions.

One of the reasons why nurses are getting a higher proportion of schoolchildren is that children who have these allergic reactions are now more likely to be sent to a school nurse than they were ten years ago. So, we have to "eliminate" this alternate cause to reach the conclusion.

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Re: Exposure to certain chemicals commonly used in elementary schools [#permalink]

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02 Mar 2015, 08:04
Choice C here, as it is assumed that nurse report cases more often leading to sn increase of accidents

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Re: Exposure to certain chemicals commonly used in elementary schools [#permalink]

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15 Mar 2015, 18:33
Choice C is the best answer.

The conclusion essentially gives two options, that children are more sensitive to chemicals or that there are more chemicals. The evidence of that (or premise), is that the proportion of children sent to them has increased over the last ten years, so we know we are looking for something that eliminates any other reason (other than those given in the conclusion) for a greater proportion of children to have gone to the nurse. C does a perfect job of that.

The other answers are wrong, because:
A is irrelevant, the reports are from all nurses not an individual
B is also irrelevant to the conclusion. Other allergies do not affect anything
D doesn't effect how much they are used, just eliminates one area they could have affected children
E the proportion of children to the overall population doesn't say anything about the proportion of children being sent to the nurse for chemical allergies
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Re: Exposure to certain chemicals commonly used in elementary schools [#permalink]

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25 Mar 2015, 17:06
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Hi there,

Argument Deconstructed

- Background (Fact): some chemicals used in elementary schools cause allergic reactions in children.
- Premise (Fact): Nurses in one particular school say that in the past 10 years, a bigger proportion of school children have been sent to them for treatment of these specific allergic reactions.
- Conclusion (Opinion): Only two explanations are possible: 1-Either children have been exposed to greater quantities of the chemical or 2-they are more sensitive than schoolchildren were ten years ago.

Negation Test
I´ll try to explain this question with the Negation Test. In other words, I will negate each answer choice to see whether the new, negated version hurts the argument or not. The one that does, will be our correct answer.

This tactic is based on the fact that an assumption is a hidden or unstated new premise for the argument. If you address a premise, this will strenghten the argument. If you address a premise but also revert its meaning (Negation Test), this will weaken the argument.

A. The number of school nurses employed by Renston’s elementary schools HAS DECREASED over the past ten years.
So what? Irrelevant

B. Children who are allergic to the chemicals are MORE LIKELY than other children to have allergies to other substances.
So what? This doesn´t actually explain the rise in the proportion of children sent to the nurses in the past 10 years.

C. Children who have allergic reactions to the chemicals are MORE LIKELY to be sent to a school nurse now than they were ten years ago.
Waaaaait a minute. This would crash the argument. The author stated that there could be only 2 reasons for the rise in number of children sent to nurses (exposure to greater quantities or more sensitiveness). If we negate this AC, this would imply that there is another (a third) possible cause.

D. The chemicals ARE commonly used as cleaners or pesticides in houses and apartment buildings in Renston.
So what? Completely irrelevant.

E. Children attending elementary school DO MAKE UP a larger proportion of Renston’s population now than they did ten years ago.
So what? This one tries to confuse you with the concept of proportions. Anyway, negating this answer doesn´t hurt the argument.
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Re: Exposure to certain chemicals commonly used in elementary schools [#permalink]

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27 Jan 2016, 20:20
subhashghosh 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.

Nice question. Chemicals cause allergic reactions. No of school children sent for treatment have increased to the number sent 10 years before.
Pre-thinking results - Did the number of children increase overall?

A - Incorrect. If it was said that the proportion of children to nurses has increased - this would be a correct answer. Incorrect.
B - doesn't matter
C - This comes closely to pre-thinking, number of children reporting started increasing.
D - doesn't matter
E - Tricky. We don't know if the population increased or decreased. Incorrect

Ans C

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Re: Exposure to certain chemicals commonly used in elementary schools [#permalink]

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28 Jan 2016, 07:49
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.
-The number of nurses would have been required if we were to calculate the of students per nurse.But since that is not the case here so eliminated this option

B. Children who are allergic to the chemicals are no more likely than other children to have allergies to other substances.

- Other allergy does not matter here.

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.

-Looks good.
IF the number of children allergic to the compounds has not changed at all , only the proportion sent to nurses changed THEN the conclusion is negated. This option removes that option and saves the conclusion

D. The chemicals are not commonly used as cleaners or pesticides in houses and apartment buildings in Renston.

- If chemicals are used commonly then the number of children getting affected will increase instead of decreasing

E. Children attending elementary school do not make up a larger proportion of Renston’s population now than they did ten years ago.
-Irrelevant
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Re: Exposure to certain chemicals commonly used in elementary schools [#permalink]

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02 Apr 2016, 19:37
I went with C
my initial assumptions:
households use more of these chemicals, so children get exposed to greater quantity
continuous exposure -> deterioration of health and thus go to doctor more often.

C looks like a good assumption.
if we negate it, then the conclusion is shattered. children before, even if they had allergy reaction, were not sent to the doc.

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Re: Exposure to certain chemicals commonly used in elementary schools [#permalink]

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16 Apr 2016, 09:21
UmangMathur wrote:
I read in most of the answer explanations that choice A is irrelevant. Choice A is wrong, but certainly not irrelevant, because if the number of nurses decrease and the number of children remain constant, then every nurse will be treating more children than he / she used to 10 years ago.

But this assumption assumes that the number of children have remain same / not decreased, thus the choice A holds wrong.

In my opinion as well, A is not irrelevant. I chose C as it made more sense but A definitely could be the reason. Also thanks for pointing out why it is incorrect.

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Re: Exposure to certain chemicals commonly used in elementary schools   [#permalink] 16 Apr 2016, 09:21

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