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Negate Method for Assumption CR

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Negate Method for Assumption CR

by yvonne0923 » Fri May 13, 2011 4:59 pm
The retail price of decaffeinated coffee is considerably higher than that of regular coffee. However, the process by which coffee beans are decaffeinated is fairly simple and not very costly. Therefore, the price difference cannot be accounted for by the greater cost of providing decaffeinated coffee to consumer.

The argument relies on assuming which one of the following?

A. Process regular coffee costs more than processing decaffeinated coffee.
B. Price differences between products can generally be accounted for by such factors as supply and demand, not by differences in production costs.
C. There is little competition among companies that process decaffeinated coffee.
D. Retail coffee-sellers do not expect that consumers are content to pay more for decaffeinated coffee than for regular coffee.
E. The beans used for producing decaffeinated coffee do not cost much more before processing than the beans used for producing regular coffee.
















I tried to use the Negate method for choice B, but I don't know if I should negate the whole sentence or part of it, so I did it like this ---- "Price differences between products cannot generally be accounted for by such facotrs as supply and demand, by differences in production costs." Then I found that this actually attack against the argument, so I chose B. Why B can not be the answer?

Correct answer: E
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by David@VeritasPrep » Fri May 13, 2011 6:33 pm
We are trying to see which assumption is required by the argument.

The conclusion is "the price difference cannot be accounted for by the greater cost of providing decaffeinated coffee to consumer."

The evidence is that "the process by which coffee beans are decaffeinated is fairly simple and not very costly."

So we can see that one of the elements that goes into decaffeinated coffee is not costly. And from this the argument concludes that the greater cost of decaff is not accounted for by the cost of providing the beans to the consumer.

However, there are other possible costs to decaffeinating. What if, as I was once told, the best decaffeinating only takes place in Germany and all beans have to be flown there and then flown to other countries for sale? That would mean that even though the process is cheap the beans could still be more expensive to provide to the consumer.

Now excluding the above scenario would be an assumption that would point toward the conclusion that the extra cost of decaf is just profit and not the cost of providing the beans. So one possible correct answer to this question is "The coffee beans used for decaffeinated coffee do not have to be flown thousands of extra miles just for the decaffeinating process."

Now that answer is not here, but answer choice E serves the same purpose, because it says that "The beans used for producing decaffeinated coffee do not cost much more before processing than the beans used for producing regular coffee" so this eliminates another of the possible costs of decaffeinating coffee."

If you were looking to negate answer choice E then it would become "The beans used for producing decaf coffee DO COST much more before processing..." and this directly weakens the conclusion.

As to choice B, we are looking for an assumption required for this conclusion -- specifically about coffee beans. You would never want to even spend time negating choice B because as a rule this type of answer choice will never be an assumption of this conclusion.

Choice B says, "Price differences between products can generally be accounted for by such factors as supply and demand, not by differences in production costs." But this conclusion - about coffee beans - is not assuming anything about what is generally true of price differences.

For example, I might try to explain why even though Apple products are so much more expensive than other products of similar quality. It does no good to say that "in general price is the most important factor when consumer choose between comparable products." You see we are trying to explain this particular situation, and it would never be a REQUIRED ASSUMPTION that something be true of products in general.

One more example, in trying to explain why Michael Jordan was so good at dunking the basketball I am surely not assuming that most people can dunk a basketball. The best assumption answer for the conclusion "Michael Jordan can dunk" is "at least one human can dunk" because if that is not true then the conclusion fails.
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by vikram4689 » Fri May 13, 2011 6:38 pm
Well the language of options is a bit convoluted.... i chose B in hurry as timer was going over 2min but later i realized that B has some loop hole and E is correct

Option B. Price differences between products can generally be accounted for by such factors as supply and demand, not by differences in production costs.

Negation of B : Price differences between products CANNOT generally be accounted for by such factors as supply and demand, BUT by differences in production costs.

Simplifying Neg of B: Price diff can be accounted for diff in prod. costs but not for supply and demand. Here the loop hole is that there can be other reason for price diff. as negation does not say "Price diff can be accounted for diff in prod. costs ONLY"

While neg of E says price of beans used for producing decaff coffee is much more than that of beans for prod. reg. coffee and this hurts the arg and hence is CORRECT.
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by David@VeritasPrep » Fri May 13, 2011 6:54 pm
Vikram -

I certainly take your point about the loophole and it is a good one, But why negate B at all?

As per my post above, the correct "required assumption" will almost never be that something is "generally true." Why would it be required that something be generally true when we have a specific instance?

The fewer choices you can try to negate on an assumption question the better! Eliminate the ones that you can first and negate the ones that are still around...
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by vikram4689 » Sat May 14, 2011 9:28 pm
Hi David,
Thats good time saver tip, is the reason behind this is that what is GENERALLY true/false MAY/MAY NOT apply to the specific case at hand.

In that case, if i modify the statement B to following , would it be necessary to use negation and contemplate instead of directly rejecting as was done in earlier case
In case of coffee industry, Price differences between products can be accounted for by such factors as supply and demand, not by differences in production costs.

Does this rule apply to any other categories ??

Thanks
Vikram
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by bblast » Sat May 14, 2011 9:50 pm
This is a good question. Whats the source ?

At first look even I reached option B. But before finalizing I applied the negation technique and I realized it was actually E.

Take away-always confirm with negation test (spend 10 seconds) before moving ahead with an assumption answer.
Last edited by bblast on Sun May 15, 2011 6:07 am, edited 1 time in total.
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by mundasingh123 » Sat May 14, 2011 10:45 pm
David@VeritasPrep wrote:Vikram -

I certainly take your point about the loophole and it is a good one, But why negate B at all?

As per my post above, the correct "required assumption" will almost never be that something is "generally true." Why would it be required that something be generally true when we have a specific instance?

The fewer choices you can try to negate on an assumption question the better! Eliminate the ones that you can first and negate the ones that are still around...
Hi david you said that answer choices that are true in general can never be the OA on GMAT . Is this true even for Strengthen and weaken questions ?
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by David@VeritasPrep » Sun May 15, 2011 5:59 am
This is an good question. Whats the source ?
Thanks "BBlast" it is a good assumption question. The source is the Veritas Critical Reasoning 2 book. This is question 86 out of 103. The Critical Reasoning 2 book has plenty of advanced questions including lots of assumptions. It also has techniques for addressing the types of questions that students often need some extra help with like Plan questions, Flaw Questions, Useful to Evaluate, and Best completes the passage.

Okay enough of my love for the Critical Reasoning 2 book (full disclosure, I wrote some of the questions in this book - although not the one we are discussing)

The techniques and tips discussed on this question are ONLY for Assumption questions.

Remember that an assumption is something that is being relied upon (even if not directly stated) so an assumption is something that gives you results WHEN TAKEN AWAY. On a normal strengthen question the answer choice gives you results WHEN ADDED to the argument.

Quick example. Let's go to the Olympics and specifically to the Jamaican sprinter Usain Bolt.

Here is the conclusion of the argument: "Usain Bolt can run 100 meters in less than 9.7 seconds"

Now try out these two answer choices.

A) Most humans can run 100 meters in less than 9.7 seconds.

B) It is possible to run 100 meters in less than 9.7 seconds.

Which of these is the assumption answer choice?


Choice B is the assumption choice here. This is the one that is required by the conclusion. Use the negation technique here and you see that it becomes "It is NOT possible to run 100 meters in 9.7 seconds." You can see that this certainly harms the conclusion that Usain Bolt can run in under 9.7.

Choice A above is a decent strengthen choice. If most people can do something than it does help the conclusion that this particular guy can do it. Even better would be to say that "ALL people can run it in under 9.7 seconds" However if you negate these choices you see that these are not required for the conclusion. Negate choice A to say "fewer than half (this is the opposite of most) of people can run 100 meters in less than 9.7 seconds." This does not really harm the conclusion that Usain Bolt can run it that fast.

So this should help you to see that negation does not work for strengthen or weaken questions and also why, as discussed above, something like "generally" or "most" does not make for a good assumption answer choice. It is because very few conclusions actually require that "most" people do something. In the above, what is true of coffee prices does not NEED to be true GENERALLY.
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by David@VeritasPrep » Sun May 15, 2011 6:19 am
Hi David,
Thats good time saver tip, is the reason behind this is that what is GENERALLY true/false MAY/MAY NOT apply to the specific case at hand.

In that case, if i modify the statement B to following , would it be necessary to use negation and contemplate instead of directly rejecting as was done in earlier case
In case of coffee industry, Price differences between products can be accounted for by such factors as supply and demand, not by differences in production costs.

Does this rule apply to any other categories ??

Thanks
Vikram

Vikram -

This is a good question. It shows that you are really working to understand these assumption questions. Where you say
is the reason behind this is that what is GENERALLY true/false MAY/MAY NOT apply to the specific case at hand.
This is not exactly it...the way that you are thinking of this is as strengthen question. You are still thinking of adding the answer choice. You say that the problem is that it might not apply to the case at hand. THIS IS NOT THE WAY for an assumption question. Remember that for an assumption question the correct answer is one that is required by the argument. So the problem with B is not that it might not apply, the problem is that the conclusion can survive without it.

As in my example above answer choice A, using the word "most", if you take this answer away then you can still have the conclusion about Usain Bolt running under 9.7 seconds. So the problem is not that Bolt may be part of the minority who cannot run that fast, rather the problem is that for him to run that fast it is not required that most people be able to run that fast.

Does that help?
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by mundasingh123 » Sun May 15, 2011 9:46 am
Hi David , Regarding the example of Bolt that you gave , doest "less than half people can run 100 metres in 9.97 s " strengthen the statement .
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by Jayanth2689 » Sun May 15, 2011 10:31 am
Hi David,

Thanks for the detailed explanation and for the usain bolt example...although i got this question right, i did not use the negation technique! my logic was...the stem talks ONLY about the cost of processing the coffee beans..whereas the actual cost of the BEANS by themselves (before processing) is assumed to be more or less the same..so E fits the bill wo any negation..am i right in this approach?
yvonne0923 wrote:The retail price of decaffeinated coffee is considerably higher than that of regular coffee. However, the process by which coffee beans are decaffeinated is fairly simple and not very costly. Therefore, the price difference cannot be accounted for by the greater cost of providing decaffeinated coffee to consumer.

Correct answer: E
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by yvonne0923 » Sun May 15, 2011 11:31 am
David@VeritasPrep wrote:
For example, I might try to explain why even though Apple products are so much more expensive than other products of similar quality. It does no good to say that "in general price is the most important factor when consumer choose between comparable products." You see we are trying to explain this particular situation, and it would never be a REQUIRED ASSUMPTION that something be true of products in general.

Thanks for your alternative explanation of "apple products." I only concerned the relationship between "price differences" and "production costs", so that I generalized the argument.
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by vikram4689 » Sun May 15, 2011 3:48 pm
Mundasingh:
If fewer than half people can do a particular task than we CANNOT say that chances are high that a particular person will do it. However, if Most of people can do a particular task than we CAN say that chances are high that a particular person will do it. Remember even the second statement does not fully confirms that person will successfully do the task but it certainly strengthens whereas first statement DOES NOT even strengthen.

Jayanth: You did in most effective manner, negation test is to be used only in cases where we are not able to finalize an option otherwise.

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by Jayanth2689 » Sun May 15, 2011 5:08 pm
@ Vikram - Cool!
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by David@VeritasPrep » Sun May 15, 2011 6:10 pm
Vikram is exactly right...

Definitely you want to try to think in your mind (is this answer REQUIRED for the conclusion?)

Like Vikram I can usually do these problems without actually negating the choices.

The key is to eliminate those choices that are not required by the argument - and as you read each answer just think - "what if this is not here?"

Also, many choices are of course outside the scope or in other ways easily eliminated.

The negation technique is a valuable tool, but not to be used unless it is needed. Sometimes it is more than it is worth to try to negate some convoluted answer that is outside the scope anyway!
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