Q10 - Although the charter of Westside

[noah]

This question asks us to add a new assumption/new piece of information to the premises already given to reach the conclusion of the argument. That conclusion is: "The school is currently in violation of its charter."

In a question like this, it often helps to identify what might be an assumption of the argument (something that is not stated that needs to be true for the argument to work) - that assumption should be the answer. Let's look at the premises we have. The author tells us that the Westside School (WS) has to enroll students with special needs (SN). They also tell us that there are no students with learning disabilities (LD) and finds that this means they must be violating their charter.

Since we know only one thing about the charter, our attention necessarily goes to the question of whether WS is fulfilling its requirement with respect to SN students. But does SN=LD? Isn't it possible that some students with SN don't have LD? There could be other kinds of SN - maybe physical or emotional? This may seem like I'm bringing in outside knowledge, but I'm not. I'm mostly just thinking that since the premises didn't tell met hat SN=LD, I would be wrong to assume that they are the same. However, doesn't the author seem to be treating these as the same?

For an analogous argument, what if I were to say. My high school clique has to have an athlete to be a cool clique. But my high school clique doesn't have any lacrosse players, therefore it is not a cool clique. This argument is making a very similar assumption - do you see what it is?

Answer choice (D) gets right at this assumption by saying that any student with SN necessarily also has LD. This is not the same as what I had anticipated (that SN =LD), but it is the same for logical purposes, mainly saying that when there are no LD students there are no SN students. Bingo!

So why is answer choice (B) incorrect? I would say there are two reasons. First, (B) restates a premise - we already know that there are no students with LD in the school at present. If it is explicitly stated already, it won't help us to restate it or to assume it. Another reason (B) is incorrect is that it doesn't address the charter requirement. Remember, the charter is about SN not LD. Therefore, we probably need an assumption that involves SN on some level.

I hope this helps!

(P.S. This was actually written by Aileen, but it ended up in the wrong area).

[geverett]

Quick question on this one:

Alright so the argument in the stimulus is assuming this:

~LD ----> ~SN
or contrapositive
SN -----> LD

The tricky part was deciphering what D vs. A.

A is a mistaken reversal because it is saying:

LD -----> SN

However I would like further clarification on the term "The only . . ." as cited in answer choice D. Is this term distinct from "only" in that "the only" is used to introduce a sufficient condition? I looked at answer choice D and kept wanting to write it out the same way as A: LD --->SN but I am thinking it actually needs to be written out SN ----> LD. Can you provide further clarification on "the only" as I believe I have seen it used this way in other areas on the LSAT. Thanks!

[noah]

Good question.

This issue is why a programmatic approach to deciphering necessary and sufficient keywords can end up keeping folks from top scores.

Let's take this statement: "the only people who can go to the party are veterans."

What do you know for sure?

You know that if someone is at the party, they're a vet (party --> vet).

If someone is a vet, obviously, they don't have to be at the party.

So, here, the "only" is applying to the vets.

This grammatical construction shows up in various places, but instead of suggesting that you memorize this one, I'd say to use your common sense for these statements to decipher them.

[geverett]

That absolutely rocks Noah. Thanks!

[velvet]

In the Manhattan book it says, "So, the argument assumes that if there are no LD, then there are no SN, right?" It then expresses the premise as a conditional: ~LD --> ~SN.

First off, when I read the premise I never even considered this to be making a conditional relationship. I'm guessing this is one of those "conditionals in disguise" that you talk about?

And how exactly are you able to come up with this conditional from "some students" in the stimulus? I understood that only absolute quantities (All, None, etc...) can be expressed as conditionals, and not indeterminate quantities such as "some."

[noah]

In the Manhattan book it says, "So, the argument assumes that if there are no LD, then there are no SN, right?" It then expresses the premise as a conditional: ~LD --> ~SN.

First off, when I read the premise I never even considered this to be making a conditional relationship. I'm guessing this is one of those "conditionals in disguise" that you talk about?

The part you're quoting is talking about what the argument assumes. So, it's not written in the argument.

And how exactly are you able to come up with this conditional from "some students" in the stimulus? I understood that only absolute quantities (All, None, etc...) can be expressed as conditionals, and not indeterminate quantities such as "some."

You're right to be wary of turning a "some statement" into a conditional. However, in this case, the some isn't referring to how often something should happen. Take a look at these two statements:

1. John will sometimes bike to work when it's sunny.

2. When it's sunny, John will bring some cherries to work.

See the difference?

In the first one, it sometimes occurs. In the second, it always occurs, and what is occurring involves an unknown amount.

That clear it up?

[velvet]

Yes! Thanks!

[raziel]

I knew the answer was (D) because it fit with the gap in the stimulus. However, I had a little bit of trouble seeing the relationship. I knew that the only was referring to the students with learning disabilities so the relationship was SE==>LD. But when reading it I couldn't picture exactly how it worked. But then I used "No learning disabilities, no special education needs" which seems much easier to symbolize and clearly means the same thing . It may be easier for some people to also think about the only relationship in this way.

[HoodyHoo]

How can you prove that A is wrong? What stops us from making that assumption?

[courtney_chrusch]

Hello, why would A be wrong? If it's talking about "The only" as sufficient, couldn't A be a viable option too? Or is it wrong just because the language is too strong?

Thanks!

[ohthatpatrick]

There's no such thing as "too strong" on any question stem that is saying,

Which of the following, if true / if valid / if assumed

That wording is saying, "If you pretend each answer choice is true, would it do anything?"

You're attracted to (A) because it's a Necessary Assumption.

If students with learning disabilities were NOT students with special educational needs, then the author's premise about "no students with learning disabilities" would be irrelevant.

Thus, the author IS definitely assuming (A).
(When we say the author IS assuming something, we mean Necessary Assumption)

But this is Sufficient Assumption. Our correct answer is supposed to PROVE the conclusion.

If we add (A) to our other premises, would we be able to derive the conclusion?

All students with LD's have SEN's.
There are no students if LD's enrolled at Westside.
Westside's charter said that it MUST enroll some SEN's.
=====
Thus, Westside is in violation of its charter.

This doesn't guarantee the conclusion.

Here's an analogous argument:

Pam is a friend of mine.
Pam is not going to be at the party.
If I don't have any friends at this party, the party will suck.
=====
Thus, the party will suck.

Have I proven to you that the party will suck?

Of course not! What if one of my OTHER friends is at the party?

That's the same reason why (A) doesn't prove the conclusion:
Great, we know that students with LD's have special needs, and we know that there are no students with LD's at the school.

But that doesn't prove there are no students with special needs at the school! Maybe there OTHER students, besides the ones with LD's, who also have special needs (perhaps a blind student).

I hope this appeases. Let me know if not.

[AlexY297]

In the Manhattan Book on p. 345 when explaining A) All students have learning disabilities have special needs.

This becomes LD--> SN
Contrapositive: Not SN--> Not LD

But then it says: "What do you think of A now? It's the exact negation what we need! We need: Not LD--> Not SN

I think this might be a typo? It is the reversal of what we need not exact negation.

Thanks,
Alex