Critical Reasoning

I'm stuck between C and D ..what is the answer?

deepshi291 wrote:I'm stuck between C and D ..what is the answer?

The official answer as well as some thorough explanations are posted on the previous page.

DanaJ wrote:OK I'll try to give you an example. However, just a bit of advice: this type of question is VERY common and among the easier of CR questions. If you do not understand it properly and pretty fast, you might get into trouble later on. It's doable! You can do it!
You have the following case: the school had 500 children ten years ago and has 500 children now as well. At present, 10 kids come to the nurse with allergies. In 2000, only 5 kids came to the nurse.

The proportion is obviously bigger now than 10 years ago, since 10/500 > 5/500.

So let's take C and negate it. We have:

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

This tells us that the kids' supervisors are more cautious today than they were ten years ago. This could mean that ten years ago 11 kids were allergic to the substances, but fewer were sent to the nurse because teachers were not paying attention. If this is the case, then the argument falls apart because there is an ALTERNATIVE EXPLANATION to the increase in proportion: teachers' care.

About E: I never said E is about other children. The argument concerns strictly schoolchildren and the proportion of allergic kids among schoolchildren. Proportions involving something other than schoolchildren are irrelevant to the argument.

E is playing on your attention. The argument strictly says "proportion of schoolchildren sent to the nurse". E suggests that the population might have changed, so the total number of kids sent to the nurse is different. However, the TOTAL NUMBER is not important, it's just the proportion.

man!!!
please reread the option C
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.
it said " not more likely" . thus the explaination is not made sense, i dont understand

Testluv wrote:

paddle_sweep wrote:I will go with 'A'. Pls post OA and also please quote the source.

Hi,

the correct answer is most certainly choice C as DanaJ thoroughly discussed.

But I can see why choice A is tempting you! However, the passage discusses the "elementary school nurses" as a group. It doesn't say that each individual nurse is now receiving more of such students. So, the reasoning of the argument does not depend on the idea that there aren't more nurses than there used to be.

if the option C " 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." as diana said, it would make sense and i agree but the option C stated that " 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. " it mean the number of students sent to school's nurses today are not >>> 10 years ago, it can be equal or <<<
i still dont understand why its C

A common test to see if an option is an assumption of a certain argument is to negate it and see if the argument falls apart. That is exactly what I did in the post above.

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. Out of scope. Has no affect on the proportion of children sent to the nurse.

B. Children who are allergic to the chemicals are no more likely than other children to have allergies to other substances. Out of scope. The argument isn't about 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. Correct. The argument assumes that there were no other reasons that the children were sent to the nurse. Also, this answer choice fails the negation test. Negated, this answer says that the children with the allergies were more likely to be sent to the nurse. If the children were more likely to be sent to the nurse for other reasons, we can't know for a fact that the chemicals were to blame.

D. The chemicals are not commonly used as cleaners or pesticides in houses and apartment buildings in Renston. Out of scope. The argument is not about where the children were exposed to the chemicals. Remember: the assumption is an answer choice that MUST BE TRUE for the argument to hold together. Why would it have to be true that the chemicals were not commonly used in the homes of the children?

E. Children attending elementary school do not make up a larger proportion of Renston�s population now than they did ten years ago. Not the assumption. The argument is not comparing the elementary school children to the the rest of the population. It is comparing comparing elementary school children with the allergies to elementary school children without the allergies. How the elementary school children relate to the whole population is irrelevant.

The correct answer is C. It is the only answer choice that must be true for the argument to hold together.

Remember: the assumption is an answer choice that MUST BE TRUE for the argument to hold together. If an answer choice doesn't have to be true, eliminate it.

(A useful test for assumption questions is the negation test. When you negate the correct answer choice -- when you make the answer say the opposite of what it says -- the argument will fall apart. How does this help us? Because if the argument falls apart when the answer choice is negated, then the answer choice must be true for the argument to hold together. And the assumption is exactly that: the thing that must be true for the argument to hold together. Any answer choice that fails this test can be eliminated.)

Hope this helps!

kiranlegend 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.

As "C" says , I'm lil confused with the sentence ..

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.


I'm reading it as ten years ago affected children used to go more than today. "Not more likely to be sent ... than then were ten years ago..

Am I reading it wrong ?? Please correct.

DonPaw wrote:

kiranlegend 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.

As "C" says , I'm lil confused with the sentence ..

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.


I'm reading it as ten years ago affected children used to go more than today. "Not more likely to be sent ... than then were ten years ago..

Am I reading it wrong ?? Please correct.

Yes, I think that you are misreading answer choice C. The answer choices are not offered as statements of fact; they are offered only as what the argument is assuming to be true.

A take-away for assumption questions:

As you read each answer choice, start with the words "The argument assumes that [insert answer choice]."

Applying this strategy to answer choice C, we get:

The argument assumes that 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.

Yes, this is what the argument assumes: that the allergic children are not more likely to be sent to the nurse, regardless of the reason. If the children are being sent to the nurse for reasons that have nothing to do with their allergies, the argument falls apart.

Does this clarify why answer choice C is correct?

GMATGuruNY wrote:

DonPaw wrote:

kiranlegend 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.

As "C" says , I'm lil confused with the sentence ..

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.


I'm reading it as ten years ago affected children used to go more than today. "Not more likely to be sent ... than then were ten years ago..

Am I reading it wrong ?? Please correct.

Yes, I think that you are misreading answer choice C. The answer choices are not offered as statements of fact; they are offered only as what the argument is assuming to be true.

A take-away for assumption questions:

As you read each answer choice, start with the words "The argument assumes that [insert answer choice]."

Applying this strategy to answer choice C, we get:

The argument assumes that 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.

Yes, this is what the argument assumes: that the allergic children are not more likely to be sent to the nurse, regardless of the reason. If the children are being sent to the nurse for reasons that have nothing to do with their allergies, the argument falls apart.

Does this clarify why answer choice C is correct?

Thanks GMATGuruNY !!

and I understood your point of view still feel that "not more likely" conveys a different meaning. I guess it is fault from my side. I'll try to run this specific sentence to see how other understand it out of this context.

kiranlegend 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.

IMO C
More children with the allergies are sent to the nurses that were ten years ago----------this can be a scenario that is taken for granted in the argument.

yippppiiieeee...... its C

A. The number of school nurses employed by Renston's elementary schools has not decreased
over the past ten years.

So if I negate this option: the number of nurses go down the proportion would go up...so why not this option?

CaptainM wrote:A. The number of school nurses employed by Renston's elementary schools has not decreased
over the past ten years.

So if I negate this option: the number of nurses go down the proportion would go up...so why not this option?

The children are being sent to the nurses. The argument is about why the children are being sent. The number of nurses doesn't affect why the children are being sent to the nurses.

GMATGuruNY wrote:

CaptainM wrote:A. The number of school nurses employed by Renston's elementary schools has not decreased
over the past ten years.

So if I negate this option: the number of nurses go down the proportion would go up...so why not this option?

The children are being sent to the nurses. The argument is about why the children are being sent. The number of nurses doesn't affect why the children are being sent to the nurses.

Thanks a lot for the quick reply!!!

I am a still confused...plz help

"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."

Option A says the number of nurses went down.
Say for example:
Total no of children affected: 100 total no. of nurses : 100 so the each nurse gets 1 child
Total no of children affected: 100 total no. of nurses : less than 100 => each nurse gets more number of children

So the conclusion falls apart as we have another reason for the increase.

(C) also gives another reason for the increase than the given conclusion.

CaptainM wrote:

GMATGuruNY wrote:

CaptainM wrote:A. The number of school nurses employed by Renston's elementary schools has not decreased
over the past ten years.

So if I negate this option: the number of nurses go down the proportion would go up...so why not this option?

The children are being sent to the nurses. The argument is about why the children are being sent. The number of nurses doesn't affect why the children are being sent to the nurses.

Thanks a lot for the quick reply!!!

I am a still confused...plz help

"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."

Option A says the number of nurses went down.
Say for example:
Total no of children affected: 100 total no. of nurses : 100 so the each nurse gets 1 child
Total no of children affected: 100 total no. of nurses : less than 100 => each nurse gets more number of children

So the conclusion falls apart as we have another reason for the increase.

(C) also gives another reason for the increase than the given conclusion.

The proportion of schoolchildren sent to them for treatment of allergic reactions does not mean the number of children per nurse. It means:

number of children sent for treatment of allergic reactions/total number of children

In other words, out of all the children, how many were sent to the nurses in order to be treated for allergic reactions to the chemicals? The number of nurses is irrelevant, so answer choice A can be eliminated.

Does this help?