Everyone who has graduated from TopNotch High School

[Aragorn]

This CR Question is from MGMAT test

Everyone who has graduated from TopNotch High School has an intelligence quotient (IQ) of over 120. Most students with an IQ of over 120 and all students with an IQ of over 150 who apply to one or more Ivy League universities are accepted to at least one of them.

The statements above, if true, best support which of the following conclusions?

(a) Every graduate of TopNotch High School with an IQ of 150 has been accepted to at least one Ivy-League school.
(b) If a person is a high-school graduate and has an IQ of less than 100, he or she could not have been a student at TopNotch High School.
(c) If a person has an IQ of 130 and is attending an Ivy-League school, it is possible for him or her to have graduated from TopNotch High School.
(d) At least one graduate from TopNotch high school who has applied to at least one Ivy-League university has been accepted to one of them.
(e) If a high-school graduate has an IQ of 150 and is not attending an Ivy-League school, then he or she did not apply to one of them.

[Aragorn]

I was going for (D)

Argument states that:
'Everyone who has graduated from TopNotch High School has an intelligence quotient (IQ) of over 120'
in my words: all graduates from HS have IQ >120

'Most students with an IQ of over 120 and all students with an IQ of over 150 who apply to one or more Ivy League universities are accepted to at least one of them.'
In my words: (Most 120 and all 150) + apply = at least one admit

so, D says...At least one graduate from TopNotch high school who has applied to at least one Ivy-League university has been accepted to one of them.

in my words... If most gradutes with IQ>120 +apply get admit. Atleast one with IQ>120 +apply will get admit.

The OA is C
For D, mgmat writes:

Hence, even if it is unlikely, it is possible that none of the TopNotch graduates had IQ of over 150, and, of the remaining graduates who applied to the Ivy League, none were accepted to an Ivy League university. This conclusion is thereby not valid.

But please tell me if most 120 get admit, how is it possible that not even 1 (one) 120 will get an admit? Otherwise, the premise in the stimulus is incorrect.

[RonPurewal]

But please tell me if most 120 get admit, how is it possible that not even 1 (one) 120 will get an admit? Otherwise, the premise in the stimulus is incorrect.

well, the problem is that the passage doesn't give any indication of how many TNHS graduates actually apply to ivy league schools. in fact, even if none of TNHS's graduates applied to ivy league schools, that is still perfectly consistent with the information presented in the passage.

so, let's say that only 1 graduate of TNHS applied to an ivy league school. while it's more likely than not that this student would be accepted, there's a decent chance that (s)he wouldn't be - and that's enough to shoot down choice (d), because it contradicts the definitive language of (d). in other words, we can't be 100% sure that at least one applicant has been accepted.
were choice (d) to make a slightly weaker statement, such as 'it is very likely that...', that would be another story - but, unfortunately, it doesn't say that.

choice (c), on the other hand, makes a very weak, anodyne statement (it is possible...), so it's very easily supported by the content of the passage.

[Aragorn]

Thanks, it is a reverse extreme words trick..if there is one.

[DCE]

Down to B and C, I chose B.

C has a very weak statement

Regards,
DCE

[RonPurewal]

Down to B and C, I chose B.

C has a very weak statement

Regards,
DCE

the "very weak statement" in choice (c) makes that choice a BETTER candidate for the correct answer. in particular, the "weaker" the statement, the more likely it is to be completely supported by the evidence in the passage!
strong statements, such as "could not have been..." in choice (b), are difficult (albeit not impossible) to support, and should be regarded with suspicion.

the problem with choice (b) is that we are only given information about the graduates of TNHS. this leaves open the possibility that TNHS has former students with iq's below 120 who failed to graduate; that possibility is enough to kill choice (b), because you aren't able to support the absolute nature of the phrase "could not have been".

[tathagat]

Hi,
I discarded Choice E because it talks of IQ = 150
Whereas, the passage talks about IQ>150

MGMAT explanations do not highlight this point.
Was my reasoning OK?

[esledge]

tathagat, the fact that 150 is a threshhold value mentioned in the problem makes (E) worth a second look. It's risky to reject it based solely on the number. I've italicized the words that I think are most relevant.

e) If a high-school graduate has an IQ of 150 and is not attending an Ivy-League school, then he or she did not apply to one of them.

The negative statements are an attempt to flip the positive premise "all students with an IQ of over 150 who apply to one or more Ivy League universities are accepted to at least one of them"

(E) is not a valid GMAT conclusion because of not only the mismatch between exactly 150 and over 150, but also the mismatch between attending and being accepted at an Ivy-League school.

[ll2318]

I struggled between B and C for a while and eventually just chose B because it was based on only 1 premise and thus was more likely to be correct. After reading the solution I understand the validity of C but am skeptical that the GMAT would be so tricky as to put an answer such as B as one of the choices. Is it really necessary to be approach questions this cautiously?

[RonPurewal]

I struggled between B and C for a while and eventually just chose B because it was based on only 1 premise and thus was more likely to be correct.

whoa there. totally faulty reasoning.

if a Draw Conclusion answer choice is based on "only 1 premise", then it's much, much, MUCH more likely to be WRONG.

takeaway:
the correct answers to almost ALL Draw Conclusion problems are based on COMBINING more than one of the premises.
almost all of them. in fact, this is basically the entire point of Draw Conclusion passages: you can't introduce anything new into the passage, so the point is to see what you can deduce by putting the premises together.
this pattern is so pervasive that, if you see an answer choice that appears to be based on only one premise, you should be very suspicious of that choice.

--

note, by the way, that RC Inference questions do NOT work this way.
RC Inference questions are almost always based on exactly one premise in the passage. (the challenge, of course, lies in locating that one premise. while that's trivial in CR passages, which are only a few lines long at most, it can sometimes be extremely difficult on RC passages.)

[mikrodj]

But please tell me if most 120 get admit, how is it possible that not even 1 (one) 120 will get an admit? Otherwise, the premise in the stimulus is incorrect.

well, the problem is that the passage doesn't give any indication of how many TNHS graduates actually apply to ivy league schools. in fact, even if none of TNHS's graduates applied to ivy league schools, that is still perfectly consistent with the information presented in the passage.

so, let's say that only 1 graduate of TNHS applied to an ivy league school. while it's more likely than not that this student would be accepted, there's a decent chance that (s)he wouldn't be - and that's enough to shoot down choice (d), because it contradicts the definitive language of (d). in other words, we can't be 100% sure that at least one applicant has been accepted.
were choice (d) to make a slightly weaker statement, such as 'it is very likely that...', that would be another story - but, unfortunately, it doesn't say that.

choice (c), on the other hand, makes a very weak, anodyne statement (it is possible...), so it's very easily supported by the content of the passage.

Hi Ron, I have a couple of questions about option D.

"At least one graduate from TopNotch high school who has applied to at least one Ivy-League university has been accepted to one of them"

Since we can consider D true, my interpretation of "At least one graduate from TopNotch high school who has applied" is that more than one student applied.

In addition, even if you want to consider the case that only one applied, I believe that "most" implies more than half of the students who applied, in that case the only student. So that student must have been accepted.

Tell me why my reasoning is wrong
Thank you in advance.

[ryan.m.doyle]

mikrodj,

I agree with you that D must be true. If "Most students with an IQ of over 120 ... who apply ... are accepted to at least one of them", then "At least one graduate ... has applied ... has been accepted to one of them" must be true. The possibility of having 0 students apply crossed my mind, but I don't agree with the logic to exclude this choice because of that. I think that scenario contradicts the statement.

D is not the correct answer because, while it is true, it does not provide support for the above claim.

With that said, I don't see how C, which also is true, "best supports" the claim either.

IMO, D is the more definitive, true statement.

Can someone elucidate why C is supportive to the claim?

[RonPurewal]

@ mikrodj

here's your mistake:

In addition, even if you want to consider the case that only one applied, I believe that "most" implies more than half of the students who applied, in that case the only student. So that student must have been accepted.

whoa, no.

the passage gives a GENERAL statement about the GENERAL population of 120+IQ applicants: namely, that most of them get into the Ivy schools.

HOWEVER,
in no way does this have to be true for ANY GIVEN GROUP of 120+IQ students.
i.e., even if most 120+ applicants are admitted (across the nation), it's still possible for ONE SCHOOL to have, say, twenty of them, and for not a single one of those twenty to get in.

analogy:
* most cubans have brown skin. (true statement)
* i know 12 cubans.
clearly, it does not follow that 7 or more of these cubans MUST have brown skin!
same thing.

basically, you made the mistake of thinking that this statement applies to the 120+ kids AT TOPNOTCH HIGH. that's not the case. read it again; it's a statement about ALL such applicants, from anywhere.

[chitrangada.maitra]

RonPurewal

Post subject: Re: Everyone who has graduated from TopNotch High School Posted: Wed Sep 09, 2009 10:18 pm

whoa there. totally faulty reasoning.

if a Draw Conclusion answer choice is based on "only 1 premise", then it's much, much, MUCH more likely to be WRONG.

takeaway:
the correct answers to almost ALL Draw Conclusion problems are based on COMBINING more than one of the premises.
almost all of them. in fact, this is basically the entire point of Draw Conclusion passages: you can't introduce anything new into the passage, so the point is to see what you can deduce by putting the premises together.
this pattern is so pervasive that, if you see an answer choice that appears to be based on only one premise, you should be very suspicious of that choice.

Ron,
I am a little confused about the general strategy to adopt with CR. The suggestion mentioned above (sort of) contradicts the ones in the strategy guide.

"The conclusion does not need to address all of the premises. A correct answer might simply restate one or more of the premises using synonyms " SG PG 89, second last paragraph

or is it smarter to not follow rules very strictly and go with the context?

Thanks,
Chitrangada

[tim]

Hi Chitrangada,
Actually, Ron’s explanation that conclusion questions "almost always" involve more than one premise does not contradict at all with the strategy guide that says that the correct answer will restate one or more of the premises. In fact, they dovetail quite nicely. Take a closer look at what each of those statements says and it should be clear.. :)