As this is CR question, let’s start by reading the Question Stem. The question is an EVALUATE THE ARGUMENT question.

Premise: After intense use - Guitar strings go dead (become less responsive) and bright in tone

Conclusion: Dirt and Oil are responsible for this change and not material properties of the string

Let’s use POE method to get the correct answer.

(A) Determining if a metal alloy is used to make the strings used by classical guitarists
- Nature/Material of the string is not at all discussed, makes this option IRRELEVANT

(B) Determining whether classical guitarists make their strings go dead faster than do folk guitarists
- Comparison between classical and folk guitarists is IRRELEVANT, if this was supposed to be true, what do we assume that classical guitarists have dirtier hands than folk guitarists?

(C) Determining whether identical lengths of string, of the same gauge, go dead at different rates when strung on various brands of guitars
- This can be trap, if you apply your knowledge that based on the string which is mostly used there may be more oil and dirt impact on specific string, but remember this is CR, we will look only for given topic of argument. Length of the string is again IRRELEVANT

(D) Determining whether a dead string and a new string produce different qualities of sound
- Argument already mentions that there is change in the sound so this option is not valid as an answer.

(E) Determining whether smearing various substances on new guitar strings causes them to go dead
- Here the option is talking about testing various items which can make a string dead and this is what we are looking for. E is the CORRECT answer.

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Hypothesis is justified, if research could confirm smearing guitar strings go dead.

E

E is the Correct answer as it would tell whether the reason of the dead guitar strings is intense use or the exposure to dirt and oil

E has to be
we need to prove if Oil and dirt is result of strings getting dead

GMATNinja

Hello Experts,

I have a doubt on option C here. Per my understanding, the conclusion states that - Dirt and Oil, rather than changes in the material properties of the string cause them to go dead.
Here my pre thinking is :
1) Assumption: Nothing else apart from dirt and oil can cause the string to go dead. So, intense use of strings is not the reason.
2) To evaluate: we can test whether the smearing substances can cause new strings to see if they go bad.

Doubt (Option c) - I understand why E is correct. But if I apply the variance test on C. It does weaken the argument but not strengthen it.

If I apply variance test on C - Determining whether identical lengths of string, of the same gauge, go dead at different rates when strung on various brands of guitars

Yes - may weaken the conclusion because if the string go bad at different rates, then there might be other reasons that may be causing the strings to go bad and not dirt or oil.
No - It doesn't tell us anything about whether dirt or oil is causing the strings to go bad.

So my analysis is that C only weaken the conclusion and not strengthen, so for that reason, its not correct.

Is my reasoning above correct? Thanks for your help!

The researcher hypothesizes that when guitar strings go "dead" after a few weeks of intense use, dirt and oil, rather than changes in the material properties of the string, are responsible. This hypothesis does not exclude the possibility that other factors would cause the strings to go dead at different rates.

For example, say we have 10 guitars from 10 different brands all used intensely for a few weeks, and the strings on those guitars go dead at slightly different rates. In that case, it is still possible that dirt and oil were primarily responsible and that other brand factors slightly influenced the rates (or maybe the design of some brands is simply more susceptible to dirt and oil). This result would not suggest that those other factors, in the absence of dirt and oil, would cause the strings to go dead after a few weeks of intense use.

True, such an experiment could yield information that might weaken the conclusion, but we are looking for the investigation that is the "most likely to yield significant information that would help to evaluate the researcher's hypothesis." Because the experiment described in choice E specifically investigates dirt and oil, the results are likely to help us evaluate the researcher's hypothesis, and so choice E is much better than choice C.

I hope this helps!
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Guitar strings often go "dead"--become less responsive and bright in tone--after a few weeks of intense use. A researcher whose son is a classical guitarist hypothesized that dirt and oil, rather than changes in the material properties of the string, were responsible.

-- What are we looking for - Something , which can answer whether oil/dirt or material is responsible for the string to be dead.
-- Only E make sense here and is the correct answer .

Which of the following investigations is most likely to yield significant information that would help to evaluate the researcher's hypothesis?

(A) Determining if a metal alloy is used to make the strings used by classical guitarists
(B) Determining whether classical guitarists make their strings go dead faster than do folk guitarists
(C) Determining whether identical lengths of string, of the same gauge, go dead at different rates when strung on various brands of guitars
(D) Determining whether a dead string and a new string produce different qualities of sound
(E) Determining whether smearing various substances on new guitar strings causes them to go dead

Premise: Guitar string will go dead after few week of use.

Conclusion: dirt and oil, were responsible for this.

Which of the following investigations is most likely to yield significant information that would help to evaluate the researcher's hypothesis?

Pre-thinking :

So following are the experiments that we need to perform to be sure about the hypothesis. So an experiment that is on the line of our conclusion will be the best one.

(A) Determining if a metal alloy is used to make the strings used by classical guitarists --- This will not do anything to the conclusion.
(B) Determining whether classical guitarists make their strings go dead faster than do folk guitarists --- this information is not very useful to evaluate.
(C) Determining whether identical lengths of string, of the same gauge, go dead at different rates when strung on various brands of guitars --- again not of use information.
(D) Determining whether a dead string and a new string produce different qualities of sound ---- even if it will, how it is relevant
(E) Determining whether smearing various substances on new guitar strings causes them to go dead --- in this case we can know what are the items that can impact the strings. What if we come to know that dirt and oil make no impact on the string. conclusion will weakened. this is indeed the correct ans.
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One strategy for Evaluate CRs is to rephrase the answer choices as basic statements.
The correct rephrase will either strengthen or weaken the conclusion, enabling us the EVALUATE its validity.
Here, the correct rephrase must strengthen or weaken the conclusion that dirt and oil were responsible for the deadening of the son's guitar strings.

E, rephrased as a basic statement:
Smearing various substances on new guitar strings causes them to go dead.
Here, smearing various substances on new guitar strings causes them to go dead, STRENGTHENING the conclusion that dirt and oil were responsible for the deadening of the son's guitar strings.

.
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Hi Experts,

I have a question regarding choice E.

How can we safely arrive to the conclusion that the term "various substances" refers to dirt and oil? To me, it isn't clear enough.

To answer this question, we need to find the investigation that "is most likely to yield significant information that would help to evaluate the researcher's hypothesis." The researcher's hypothesis is that "dirt and oil, rather than changes in the material properties of the string, were responsible" for the guitar strings going "dead."

As with any critical reasoning question, using POE to get rid of four answer choices is the best way to arrive at the correct answer. In this case, none of the other options come close to yielding significant information about whether the change in the strings is due to dirt and oil or due to material properties of the string. So, while it isn't perfectly clear that "various substances" refer to dirt and oil, we can safely say that the investigation in (E) is most likely to yield significant information that would help to evaluate the researcher's hypothesis. For this reason, (E) is the correct answer.

I hope that helps!
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