Critical Reasoning

lunarpower wrote:

amazonviper wrote:IMO B. I believe this has to be assumed for the argument to exist since if we negate this effect, i.e. if the units that are open have more business than usual then the steep decline might not happen.

two things are wrong here.

first, this is not the proper negation. the negation of "less work" is "an EQUAL OR greater volume of work", not strictly a greater volume of work.

second, you yourself have admitted that this is a subpar choice: you included the word "might" in your explanation.
when you reverse the correct assumption, the argument MUST BECOME INVALID; there's no "might" about it.

--

the correct answer is (e).

if you negate (e), you get "BBB gets the great majority of its business from outside the county".
if that's the case, then business within the county accounts for only a small fraction of the Barn's business, and so it's impossible for the cited conditions to cause a "sharp decline" all by themselves.
therefore, this line of argument would become invalid.
(notice it's still possible that BBB's business might drop - but not for the reasons given in this particular argument.)

lunarpower wrote:

mmslf75 wrote: But guys, dont u think, E goes out of scope.. as the arguement doesnt imply outside customers ??
IMO B is more correct !!

Wat say ?

it's ok for (e) to go out of scope, since (e) is a NEGATIVE STATEMENT (i.e., a statement about what doesn't happen or isn't true).

takeaway:
if an assumption is a NEGATIVE STATEMENT (i.e., a statement about what is NOT true, or about what DOESN'T happen), then it is ALLOWED to venture outside the direct scope of the passage (as long as it's relevant).

even more precisely, if an assumption says "X does not do Y", then X must be in scope, but Y is allowed to be out of scope.

--

sample:
a sample of soil from the Esterian region was brought to a lab and analyzed for silver content. the testing methods used were valid, and the sample tested positive for silver. Therefore, there must be gold in the Esterian soil.

one CORRECT assumption here is
the sample was not contaminated with gold in transit between the Esterian region and the lab.
-- the notion of contamination is out of the original scope, but this is a negative statement (NOT contaminated) so that is ok.

--

one more example:
it is 6:00 p.m. i have to be in los angeles by 7:00 p.m. therefore, i will be late to los angeles.

one CORRECT ASSUMPTION is
it takes more than 1 hour to get from here to los angeles.
(notice that this is an AFFIRMATIVE statement - i.e., not negative - and is TOTALLY WITHIN THE SCOPE of the passage)

on the other hand, the following NEGATIVE statements are ALSO NECESSARY ASSUMPTIONS:
i cannot freeze time and teleport myself to los angeles.
little green aliens will not come from outer space and carry me to LA in less than one hour.

lunarpower wrote:

mmslf75 wrote: Takeaway...
When in ASSUMTION type u can venture out of scope only on NEGATIONS
When in STRENGTHEN/WEAKEN stay in SCOPE RIght ???

in terms of strengthen/weaken, no. in fact, strengthening or weakening an argument actually requires that you step outside the immediate scope of the argument, at least by a bit. (if you just repeat or rearrange things from within the scope of the argument, then you can't really strengthen or weaken it -- you'll just be re-hashing the same points.)

so, no, MOST correct answers on strengthen/weaken problems are noticeably outside the scope of the argument, at least in some aspect(s).
of course, these answers still have to be DIRECTLY RELEVANT to the argument: they have to have an immediate impact on the line of reasoning in the problem. i.e., even if the material of the answer choice is not mentioned in the original passage, it still must have some sort of direct impact on the argument.


--

you may be confusing strengthen/weaken problems with DRAW THE CONCLUSION problems:
which of the following conclusions is most strongly supported / may be properly drawn?
which of the following may be properly inferred?
if the statements above are true, which of the following must be true?
etc.

in these questions, you MUST stay ENTIRELY within the scope of the passage. and this time, that's including negative statements as well as affirmative statements.

lunarpower wrote:

mmslf75 wrote:Look at this CR (below with link) just confirm that here,
B is assumption right ?
and C is OA -- which strengthens

you're correct about (c). that statement has a strengthening effect, because it amplifies the importance of the buses' exhaust in contributing to the problem.

you could also weaken the argument if you had a similar statement with opposite percentages: viz., the buses don't spend much time idling at all, instead spending almost 100% of the time driving between sites.

--

(b) is not an assumption, though.

the argument expressly says:
damage to Palitito's buildings from the buses' exhaust will diminish significantly.

therefore, the argument deals ONLY with damage from the exhaust; it's completely irrelevant whether there are other kinds of damage.

if the argument had said something like "the total amount of damage (i.e., from all sources) will decrease significantly", THEN we would need some kind of assumption about bus exhaust accounting for the lion's share of that damage.
in this case, though, no such assumption is even remotely relevant, let alone required.

lunarpower wrote:

mmslf75 wrote:Q1 :
Can we have quetions with one option as assumption and other as strengthen..
How does one.. differentite then ?

hmm? not quite sure i understand what you're saying.

if you're asking, "can one question ask for an assumption and a strengthener at the same time?" then the answer is no. these are two different types of statements.

the difficulty comes when the problem asks for one of these things in a very indirect, roundabout way. for instance, if you see the following question prompt:
which of the following considerations would be most helpful to establish in order to evaluate the validity of the speaker's line of argument?
ASSUMPTIONS are things that are necessary in order for the argument to be valid. therefore, this is nothing but a very obnoxious way to say "find the assumption".

there are similarly indirect ways to ask for strengtheners/weakeners.

if you see, for instance, which of the following would be most useful to know in evaluating the force/strength of the argument?
then this is basically asking for a strengthener/weakener. (the answer choices to such questions will usually start with "Whether" rather than consisting of actual statements, so they could potentially be either strengtheners or weakeners.)

Q2

In weaken, we must hit the assumption right ??

* if you're going to try to PREDICT a weakener, then, yes, the best way to do that is to try to find the assumptions and then "hit" them.

* if you're just PICKING THROUGH THE ANSWER CHOICES, though, then it's NOT the best idea to think about assumptions. in that case, just look at each choice, and see whether that choice has any sort of direct effect on the line of reasoning in the argument.
if you're just going through the choices, you shouldn't bother with thinking about assumptions - that will just add an extra (and unnecessary) step to the process.

lunarpower wrote:

mmslf75 wrote:What i meant was can we have a question with answer choices ( just to fool the testtakers ) wherein,
Option A : Might state an assumption
Option B (or any other) : Might state a strengthner to the argument.

Basically, how does one pick between statements, in STRENGTHNER question ...
I have many times, picked the assumption in the bargain !!
Can you please throw some light here !!

ah, i see what you're saying.

if this is a FIND THE ASSUMPTION question, then this situation is possible.
assumptions must be necessary to the argument; if they are falsified or removed, the argument must actually FAIL.
most strengtheners are outside the original scope of the passage, and so would fail as assumptions.
so... yes, on FIND THE ASSUMPTION questions, it's totally possible that you'll see this. i.e., there could be (and probably will be) wrong answer choices that would strengthen the passage if they were true, but are nowhere close to being essential to the integrity of the argument.

on the other hand, this will probably not happen on STRENGTHEN problems. after all, one way to strengthen a conclusion is by verifying the truth of an assumption. (this won't often happen - most strengtheners are outside the original scope of the argument - but it's possible.)
almost all wrong answers to Strengthen problems will be genuinely irrelevant to the passage, or may even weaken the force of the argument.

lunarpower wrote:

amazonviper wrote:IMO B. I believe this has to be assumed for the argument to exist since if we negate this effect, i.e. if the units that are open have more business than usual then the steep decline might not happen.

two things are wrong here.

first, this is not the proper negation. the negation of "less work" is "an EQUAL OR greater volume of work", not strictly a greater volume of work.

second, you yourself have admitted that this is a subpar choice: you included the word "might" in your explanation.
when you reverse the correct assumption, the argument MUST BECOME INVALID; there's no "might" about it.

--

the correct answer is (e).

if you negate (e), you get "BBB gets the great majority of its business from outside the county".
if that's the case, then business within the county accounts for only a small fraction of the Barn's business, and so it's impossible for the cited conditions to cause a "sharp decline" all by themselves.
therefore, this line of argument would become invalid.
(notice it's still possible that BBB's business might drop - but not for the reasons given in this particular argument.)