#23- The higher the altitude, the thinner the air. Since

[Administrator]

[u]Complete Question Explanation[/u]

[b]Parallel Reasoning-SN. The correct answer choice is (D)[/b]

This stimulus presents a valid conclusion based on two simple premises:


[list]Premise: higher altitude = thinner air

Premise: Mexico city has higher altitude than Panama City.

Conclusion: Therefore Mexico city must have thinner air.[/list]

Since this is a parallel reasoning question, in this case we should seek the application of a simple general rule to draw a valid logical conclusion.

Answer choice (A): This answer choice cannot parallel the reasoning found in the stimulus, because it is not valid. The rule is that as [i]one[/i] gets older, that same person gets wiser—not that you are wiser than anyone younger than you! So this answer choice is clearly incorrect.

Answer choice (B): The reasoning found in this answer choice is also flawed, because the conclusion is based on limited information. Since beating is a requirement for fluffiness, there is no way to assess which cook has fluffier meringue.

Answer choice (C): Like the two incorrect answer choices above, this choice contains flawed argumentation, beginning with a general statement about the fastest runners of modern times, versus those from a decade ago. Thus we cannot draw a valid conclusion about any given individual without further information.

[b]Answer choice (D): This is the correct answer choice.[/b] Like the argument found in the stimulus, this one applies a basic general rule to draw a valid conclusion:


[list]Premise: older tree = more rings

Premise: Lou's tree is older than Theresa's tree.

Conclusion: Therefore Lou's tree must have more rings than Theresa's tree.
[/list]

Answer choice (E): This choice presents the following flawed conditional reasoning:


[list]Premise: bigger vocabulary harder to learn

Flawed conclusion: English: harder to learn therefore bigger vocabulary[/list]

As we can see, the author here is guilty of the classic Mistaken Reversal, so this reasoning is flawed and cannot possibly parallel the valid argumentation found in the stimulus.

[desmail]

Hi,

I'm having a lot of trouble with answer choice (A). Why is this wrong?

Also, for parallel questions in general, the answer choice will not match the sentences verbatim, (as in conclusion indicators will not necessarily be the same, right?) I was a little intimidated by the "therefore" in (D), even though it is a solid answer.

Thank you!
Dana

[Nikki Siclunov]

Hi Dana,

This is a tricky question, and it's not surprising that many people have trouble with it. To answer your general question first, yes - the correct AC does not have to match the stimulus verbatim (the conclusion indicators will not necessarily be the same). The fact that (D) contains the conclusion indicator "therefore" neither makes or breaks that answer choice.

The argument in the stimulus is as follows:

Higher altitude --> Thinner air
Mexico City's altitude is higher than Panama City's
----------------
Mexico City's air is thinner than Panama City's

Answer choice (D) matches this perfectly:

Older tree --> More rings
Lou's tree is older than Teresa's
----------------
Lou's tree has more rings than Teresa's

The problem with (A) is in the premise "As one gets older, one gets wiser." There is correlation between age and wisdom, but they are both qualities of the same person: the older you get (relative to yourself), the wiser you get (relative to yourself). The conclusion in (A) does not reflect the comparison in this premise, because Henrietta's being older than her daughter does not mean that she is wiser than her daughter.

Let's say the daughter is 21 years old, and Henrietta is 41. Maybe during these 21 years the daughter got wiser a lot faster than Henrietta did, whose wisdom increased only incrementally in the course of 41 years. So, it is possible that today they can be equally wise, or that the daughter is even wiser than her mom. In other words, because the premise establishes a positive correlation between two qualities relative to the same person, the rate at which they increased will also be subjective. This does not allow us to compare how wise one person is to another: it only justifies a comparison between how wise that person is today vs. how wise she herself was in the past.

The premise in answer choice (A) should have said "The older one is, the wiser one is." This would have established an absolute, across the board correlation between age and wisdom that would have allowed us to compare the wisdom of one person to the wisdom of another based on their age.

Let me know if this clears things up

[desmail]

Wow, what a great explanation! That cleared it up 100%. Thanks Nikki!

[GLMDYP]

Hi!
I'm just wondering why (A) is not equally correct if (D) is.
Thanks!

[Lucas Moreau]

Hello, GLMDYP,

I'm not surprised A gave you trouble. The difference between A and D is subtle indeed, they do look very similar to each other.

The trick is that the phrase "The older a tree is, the more rings it has" shows a more direct relationship between the age and the rings than "As one gets older, one gets wiser" shows between age and wisdom.

Imagine a 20-year-old person who is very wise and a 40-year-old person who is not wise at all. (Do you know anybody like this? ) They may both be getting wiser as they get older, but just because the 40-year-old is older than the 20-year-old does not necessarily mean that the 40-year-old is wiser than the 20-year-old.

On the other hand, with the rings of a tree, there is no way a younger tree could have more rings than an older tree. The amount of rings is strictly determined by the age.

Think of rephrasing the second phrase as "The older a person is, the wiser that person is," and the difference between that and what's in A.

Hope that helps,
Lucas Moreau
PowerScore

[martinbeslu]

I could understand why E would be wrong if this was a conditional statement, but wouldn’t the arrow be biconditional in this case? The relationship is fixed, ie. the bigger the vocabulary, the harder to learn. This would also mean the smaller the vocabulary, the easier (less hard) to learn. In the real world it doesn’t work this way, but we have to go by what is stated in the argument, which is an absolute relationship between these two variables. What if the argument in answer choice E had said the harder a language is to learn, the bigger the vocabulary a language has? Wouldn’t this direct relationship be exactly the same regardless of the order of the sentence that was written? The way I read this premise it’s not possible for a language to be harder to learn unless it has a bigger vocabulary.

Wouldn’t the same be true for the argument in the stimulus. If it had said, the thinner the air, the higher the altitude, the relationship would be the same. It would not be possible to find thinner air at a lower altitude under any circumstances according to the premise that was given. This also is not true in the real world since weather patterns could cause the atmospheric pressure at sea level to be lower than the atmospheric pressure 1000 ft above sea level in some other part of the world. However, our job is to take the premises given as fact. Isn’t the premise telling us that regardless of any outside influences this relationship always holds?

Am I not understanding these statements correctly? I have no idea why swapping the order of the sentence has any effect on the argument.

[Jay Donnell]

Hi Martinbeslu!

I think this misunderstanding may lead to bigger issues down the line, so I want to help by throwing in a number of different examples to help clear up why these claims are not in fact reversible.

Take the following statements:

The taller you are, the better you are at basketball.

The more intoxicated you are, the worse you are at driving.

The more explosions in the movie, the bigger the budget.


Each of those statements has a similar form and meaning as the statement here in the stimulus:

The higher the altitude, the thinner the air.

These statements, though at first seemingly reciprocal, are in actuality unidirectional. There may be all kinds of other reasons why someone is better at basketball (shooting, dribbling, athleticism, etc), the driving is worse (weather, visibility, road conditions, etc) or why a movie budget swells (casting higher caliber actors, re-shoots, location issues). Similarly, there may be many factors other than altitude that can account for air density, so we can't assume the reversibility of that statement to imply that the thinner the air, the higher the altitude.

I hope that those examples help bring the issue to light in a way that helps you get out of this tight spot in the future!

[Tajadas]

I don't really understand how the difference in wordings of A and E make A wrong and E right. I understand the words themselves are different, but not how they result to one wrong answer and one right answer.

Jay said "The taller you are, the better you are at basketball."

To me, the subject there is you for both the tall part and the basketball part. I would have thought this would make comparisons between different people impossible since the subject is always you, and so makes this example more like A than the stimulus (or E).

Similarly, in "The older a tree, the more rings it has", the subject is a tree both times.

Why is it not okay to use one as the subject as in A, but okay to use you in the subject in Jay's example and a tree in E?

[evelineliu]

Hi Tajadas,

The right answer choice about the older a tree gets, the more rings it has is answer choice (D). (A) is wrong not because it uses "one."

The abstracted structure of the stimulus argument is: "Some tendency in A leads to a tendency in B. Since an entity has more A than another, the first entity has more B as well." (D) parallels this more closely with "higher altitude" being parallel to "older tree," leading to "thinner air" and its parallel "more rings." (A) is not quite as precise.

Hope that helps!
Eveline