#20 - On some hot days the smog in Hillview reaches

[gen2871]

Coolio. thank you!

[Dianapoo]

Hi!

I was wondering if A would have been a Good answer if it said:

mistake a condition that sometimes accompanies unsafe smog with one that is SUFFFICIENT for it.

Say the sun is sufficent for smog: sun --> smog

The other stays the same: wind blows <-s-> sun

Put these together: wind blows <-s-> sun --> smog

Use Dave's some train and boom wind blows <-s-> smog

Now we can see why the author came to that conclusion! Thus my version of A would be an answer?

Thank you! I'm trying to get a little creative

[Adam Brinker]

Hi Diana,

Does the explanation of this question here help:
lsat/viewtopic.php?t=3463

Please let us know. Thanks!

[Dianapoo]

Hi Diana,

Does the explanation of this question here help:
lsat/viewtopic.php?t=3463

Please let us know. Thanks!

Hi Adam!

I totally get the answer, I was just seeing if my approach to a slightly altered question would have been good!

[Adam Tyson]

Yes, Diana, that would have worked, and your breakdown is correct. If "hot days" was sufficient for unsafe smog, and there were some hot days that also had the wind blowing from the east, then on at least those hot days there would be both unsafe smog and wind from the east, and the author's conclusion would have been correct rather than flawed. Nicely done!

[lsatfighter]

I have read the explanation of this question from the LR Bible. I understand why B is right, but I have some questions about E.

Is it true that there is no evidence of a correlation between smog and wind blowing? That is, since we don't know that those two occur on the same day, there is no evidence of a correlation? And if those two did occur on the same day, would that be considered a correlation?

If someone could answer those questions and further elaborate on why E is wrong, I'd appreciate it.

[lsatfighter]

Hello. Unfortunately, I have not received a response to my question. If somebody could please help me out, I'd appreciate it. Thank you in advance.

[Brook Miscoski]

lsatfighter,

When you see a standard flaw on the LSAT and are asked to identify the flaw, you should select the choice that responds directly to the standard flaw.

In this case, there is a formal logic flaw because you cannot chain two "some" statements together. You should be familiar with that prohibition and the reason for it, but in review:

Some houses are white.
Some houses are brick.

Therefore there are some white brick houses.

The problem is made simple by assigning numbers, remembering that "some" means "at least one":

1 of 10 total houses is white.
1 of 10 total houses is brick.

Now it is easy to see that there is no reason why the white house should also be a brick house. There are plenty of houses to spread those characteristics around without any overlap. Note that these are not probability claims where, given enough houses, it might be unreasonable to think that a 1/10 probability of white and 1/10 probability of brick never result in a house with both characteristics. It's just 10 houses, 1 is white, and 1 is brick. It could be 1 white brick house and 9 other houses, or it could be 1 white, 1 brick, and 8 other houses. Concluding there is definitely overlap is flawed.

Looking at answer choice (B), that choice directly states the problem just illustrated. That is ample proof that (B) is the credited response.

The reason why (E) is wrong is that there is nothing in the stimulus that would indicate that the stimulus is making a causal argument or one based on statistical correlation. It simply made a formal logic error by chaining "some" statements together. The reason why (E) is attractive to you is that you probably assume that there could be some kind of causal connection or statistical correlation between hot days, smog, and wind. However, you have to be careful and confirm whether the stimulus uses causal words or correlation words to associate these things, and it doesn't. They are simply things that happen.

[hinarizvi]

Complete Question Explanation


Flaw in the Reasoning—Formal Logic. The correct answer choice is (B)

The premises of the argument contain a Formal Logic setup:

     HD = hot days in Hillview
     SUL = smog reaches unsafe levels
     WBE = wind blows in from the east

Capture.PNG

The combination of two “some” statements does not yield
any inferences. Yet, the author draws a conclusion ( SUL WBE ) on the basis of the
relationship and you must identify the answer that explains why this conclusion is incorrect.

Answer choice (A): There is no proof in the argument that the condition of WBE sometimes
accompanies smog reaching unsafe levels—that is the mistake made by the author. The answer
would be more attractive if it read as follows:

     “mistakes a condition (WBE) that sometimes accompanies hot days in Hillview for a
     condition that sometimes accompanies unsafe levels of smog”

Answer choice (B): This is the correct answer. When two “some” statements are joined, no inference
can be drawn because the group common to both may be large enough that the two sub-elements
do not overlap. For example, let’s say there are 10 hot days in Hillview (HD), 1 day when the smog
reaches unsafe levels (SUL), and 1 day when the wind blows in from the east. Is it necessary that
the 1 day when the smog reaches unsafe levels is the same day that the wind blows in from the east?
No, but the argument concludes that is the case, and that error is described in this answer choice. For
reference purposes, here is the answer choice with each abstract item identified in parentheses after
the reference:

     “fails to recognize that one set (HD) might have some members in common with each of two
     others (SUL and WBE) even though those two other sets (SUL and WBE) have no members
     in common with each other”

Answer choice (C): This answer choice describes the Uncertain Use of a Term, but the argument is
consistent in its use of “unsafe.” Therefore, this answer is incorrect.

Answer choice (D): Each premise is plausible regardless of the truth of the conclusion.

Answer choice (E): The argument does not feature causal reasoning. The conclusion clearly states
that the two events happen together, but there is no attempt to say that one caused the other. If you
chose this answer, try to identify the causal activators in the argument—there are none.

I know 2 some statements can't yield any valid inferences, but the wording in B really threw me off. What are the "some members in common" that the set of hot days would share with SUL and WBE, are those members just hot day(s)? For example, SUL (one set) might have 1 hot day (member of another set) and WBE (one set) might have 3 hot days (member of another set), but the two 2 sets don't necessarily have to share any members (hot days that are both SUL and WBE)?

[Jeff Wren]

Hi hinarizvi,

Here is Answer B with the specific set/groups in the stimulus listed in parentheses.

"Fails to recognize that one set (the set of hot days) might have some members in common with each of two others (the set of days when the smog reaches unsafe levels and the set of days when wind blows into Hillview from the east) even though those two other sets (the set of days when the smog reaches unsafe levels and the set of days when wind blows into Hillview from the east) have no members in common with each other."