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CR WEAKEN SERIES: 3) Frequency-Dependent Foraging

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CR WEAKEN SERIES: 3) Frequency-Dependent Foraging [#permalink]

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CR WEAKEN SERIES: 3) Frequency-Dependent Foraging

Frequency-dependent foraging refers to the tendency of an individual to selectively forage on a certain species based on the relative frequency of that foraged species in the wild. Generally, the more populous a species, the more likely that species is to be selected as the primary foraged species. Surprisingly, several unrelated university sponsored laboratory experiments on bumblebees, tested with an identical foraged species, yielded dramatically different results. In some experiments, the bumblebees thrived, while in others they perished. Given that each of the experiments had comparable funding, the varying results must have been attributable to the quality of the way the experiments were maintained by the researchers conducting them.

Which one of the following, if true, casts the most doubt on the conclusion drawn above?

Ⓐ In the wild, frequency-dependent foraging among bumblebees typically occurs when any one of a small number of foraged species is present.
Ⓑ The same basic experiment design guidelines were used for each of the experiments.
Ⓒ The number of academic calendar years of experience among those who conducted the laboratory experiments varied from four years to five years.
Ⓓ The species of bumblebee used in the laboratory experiments varied from experiment to experiment.
Ⓔ A team at the same university that conducted one of the frequency-dependent foraging experiments has been accused of exaggerating the findings of an experiment conducted just two years prior.

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◀ CR WEAKEN SERIES: Question 2) Several Craverton Employees

▶ CR ASSUMPTION SERIES: Question 1) Belmont Industries
[Reveal] Spoiler: OA

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Last edited by EMPOWERgmatVerbal on 05 Jun 2015, 21:31, edited 2 times in total.
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Re: CR WEAKEN SERIES: 3) Frequency-Dependent Foraging [#permalink]

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New post 03 Jun 2015, 20:59
Srry......For this one find my reply below
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Last edited by apoorv601 on 03 Jun 2015, 21:03, edited 1 time in total.
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Re: CR WEAKEN SERIES: 3) Frequency-Dependent Foraging [#permalink]

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Hi Max,
Good to see ur post!!

Conclusion - The varying results must have been attributable to quality of the way the experiments were maintained by the researchers conducting them
Premise - Generally, the more populous a species, the more likely that species is to be selected as the primary foraged species; several unrelated university sponsored laboratory experiments on bumblebees, tested with an identical foraged species, yielded dramatically different results. In some experiments, the bumblebees thrived, while in others they perished.

The argument in the conclusion assumes a cause for the difference in results of an experiment. The things that can weaker the conclusion might be alternate causes of the conclusion, new fact that undermine the quoted cause, etc.

Ⓐ In the wild, frequency-dependent foraging among bumblebees typically occurs when any one of a small number of foraged species is present. - This if true would result in no foraging of bumblebees at all while we see from the experiment that foraging occurs in some cases and did not occur at other.

Ⓑ The same basic experiment design guidelines were used for each of the experiments. - This doesn't undermine the conclusion, while the same basic guidelines may have been used in experiment but the quality of the way the experiments were maintained by the researchers conducting them could have varied, resulting in the difference in results.

Ⓒ The number of academic calendar years of experience among those who conducted the laboratory experiments varied from four years to five years. - This statement does not help explain the difference in results; while it could be that the experience of the people conducting the research could be different but the difference in results could still be because of the quality of the of the way the experiments were maintained by the researchers conducting them

Ⓓ The species of bumblebee used in the laboratory experiments varied from experiment to experiment. - This would be the perfect answer, this presents and alternate cause to the results; if different species are used in the experiments then the difference in foraging would be dependent on the relative frequency of that foraged species

Ⓔ A team at the same university that conducted one of the frequency-dependent foraging experiments has been accused of exaggerating the findings of an experiment conducted just two years prior. - The question is about the difference in results and not that the results were exaggerated
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Re: CR WEAKEN SERIES: 3) Frequency-Dependent Foraging [#permalink]

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Premise:
More populous species = more likely it is selected to be primary foraged species

Conclusion:
ONLY the way the experiments were conducted => varying results (C => E)

Weakener:
What if some other cause resulted in this effect? (Classic trap)
For example: What if areas where more B were killed had more B to start with? And areas where less B were killed had less B to start with?
This can ALSO explain the effect in the conclusion. So, the given conclusion is NOT the ONLY reason why the effect happened.


Ⓐ In the wild, frequency-dependent foraging among bumblebees typically occurs when any one of a small number of foraged species is present. - We have to attack the conclusion, which is based on experiments performed and NOT based in wild.
Ⓑ The same basic experiment design guidelines were used for each of the experiments. -
Great, this will strengthen the conclusion because it removes the doubt that any experiment had more favorable factors than others. Basically this choice says the sample is representative of the whole.
Ⓒ The number of academic calendar years of experience among those who conducted the laboratory experiments varied from four years to five years.
Assume for a while that this choice does matter. Then we have to assume that the experience of guys somehow has the effect on the understanding of the results. But we are not given if 4-5years of experience has +ve or -ve effect on the understanding of the results (!)
Ⓓ The species of bumblebee used in the laboratory experiments varied from experiment to experiment.
Aha! This choice means that there was atleast SOME other factor that was variable in all these experiments that was ALSO responsible for "varying results", our conclusion.
Ⓔ A team at the same university that conducted one of the frequency-dependent foraging experiments has been accused of exaggerating the findings of an experiment conducted just two years prior.
Assume for a while that this choice were true. Then we have to assume that because they were accussed 2 YEARS PRIOR, means they will ALSO manipulate the results now. Don't know for sure.

Answer choice D is correct based on weakener pre-thought earlier.
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Re: CR WEAKEN SERIES: 3) Frequency-Dependent Foraging [#permalink]

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[quote="EMPOWERgmatMax"]CR WEAKEN SERIES: 3) Frequency-Dependent Foraging

Frequency-dependent foraging refers to the tendency of an individual to selectively forage on a certain species based on the relative frequency of that foraged species in the wild. Generally, the more populous a species, the more likely that species is to be selected as the primary foraged species. Surprisingly, several unrelated university sponsored laboratory experiments on bumblebees, tested with an identical foraged species, yielded dramatically different results. In some experiments, the bumblebees thrived, while in others they perished. Given that each of the experiments had comparable funding, the varying results must have been attributable to the quality of the way the experiments were maintained by the researchers conducting them.

Text in green: Premises/background.
Text in Red: Conclusion

The conclusion states that there is only 1 reason for the variation in results presented by the 2 university experiments and this reason is the quality of the way the experiments were mainitained by the researchers conducting them.

Prethinking process : As this is a weakener question, the correct answer choice will weaken the conclusion by mentioning about an alternate reasoning with a high possibility. Choice D does exactly that.

Which one of the following, if true, casts the most doubt on the conclusion drawn above?

Ⓐ In the wild, frequency-dependent foraging among bumblebees typically occurs when any one of a small number of foraged species is present.
Incorrect. Irrelevant. This option talks about the species in the wild.

Ⓑ The same basic experiment design guidelines were used for each of the experiments.
Incorrect. This choice strengthens the conclusion that the quality alone was the reason for the difference in the results.

Ⓒ The number of academic calendar years of experience among those who conducted the laboratory experiments varied from four years to five years.
Incorrect: Irrelevant. Number of years of experience is not important.

Ⓓ The species of bumblebee used in the laboratory experiments varied from experiment to experiment.
Correct. As explained in the prethinking process above. I do have a question though. How is this option correct when the premise says that the foraged species used in the experiment were identical? In GMAT, I have not seen CR arguments that attack the premises. Premises must be considered true in GMAT.

Ⓔ A team at the same university that conducted one of the frequency-dependent foraging experiments has been accused of exaggerating the findings of an experiment conducted just two years prior.
Incorrect. It might mean that the university teams have a propensity to exaggerate their findings. If anything, this choice will be equally applicable to both the research teams and as such would not harm the conclusion. If this option would have provided some sort of evidence to justify why 1 of the 2 teams would exaggerate its results, then this option could have been taken into account.
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Re: CR WEAKEN SERIES: 3) Frequency-Dependent Foraging [#permalink]

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CR WEAKEN SERIES: 3) Frequency-Dependent Foraging

Frequency-dependent foraging refers to the tendency of an individual to selectively forage on a certain species based on the relative frequency of that foraged species in the wild. Generally, the more populous a species, the more likely that species is to be selected as the primary foraged species. Surprisingly, several unrelated university sponsored laboratory experiments on bumblebees, tested with an identical foraged species, yielded dramatically different results. In some experiments, the bumblebees thrived, while in others they perished. Given that each of the experiments had comparable funding, the varying results must have been attributable to the quality of the way the experiments were maintained by the researchers conducting them.

Which one of the following, if true, casts the most doubt on the conclusion drawn above?

Ⓐ In the wild, frequency-dependent foraging among bumblebees typically occurs when any one of a small number of foraged species is present.
Ⓑ The same basic experiment design guidelines were used for each of the experiments.
Ⓒ The number of academic calendar years of experience among those who conducted the laboratory experiments varied from four years to five years.
Ⓓ The species of bumblebee used in the laboratory experiments varied from experiment to experiment.
Ⓔ A team at the same university that conducted one of the frequency-dependent foraging experiments has been accused of exaggerating the findings of an experiment conducted just two years prior.

Official Explanation

Question Type: Weaken
Boil It Down (Simplified & Abbreviated Summary of the Prompt): Cost didn’t cause different outcomes, experiment maintenance did.
Missing Information (assumption): There were no other factors that could have caused the different outcomes in the bumblebee experiements.
Goal: Find the option that presents a factor other than the maintenance of the experiments that could have caused the dramatically different outcomes.

Let’s see which option best achieves the goal:

Ⓐ This option is irrelevant since the experiments used the same foraged species and the experiments are thereby standardized in terms of foraged a species.

Ⓑ If anything, this option that the design guidelines were the same would strengthen the argument that it was the manner in which the experiment was carried out that is to blame because this option dismisses another possibility. This option is an example of a 180 choice—the opposite of what we’re looking for.

Ⓒ The number of average academic calendar years of experience is a variable that either has no clear impact on the argument, or one that might even reinforce the notion that it was THE MANNER in which the experiments were carried out were to blame.


Ⓓ Yes! This option gives another possible factor for the differing bumblebee results OTHER THAN the manner in which the experiments were carried out. It was the difference in bumblebee species that’s to blame for the different results, and not the manner in which the experiments were conducted. With this option, maybe the manner in which the experiments were carried out was exactly the same, it’s just that different species of bumblebee responded to the experiment in different ways (unfortunately, some perished).

Ⓔ This option fails in a couple of ways. First, if any misconduct happened in another study at the same university how can we make the leap that because one study is suspected of being tampered with that the bumblebee study was tampered with too? We can’t. Secondly, the malfeasance is only suspected. It hasn’t even been proven yet. E sounds like it might be a negative for the argument because it provides another issue, but the problem is that the other issue is ENTIRELY irrelevant from what’s offered in the language.

◀ CR WEAKEN SERIES: Question 2) Several Craverton Employees

▶ CR ASSUMPTION SERIES: Question 1) Belmont Industries
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Re: CR WEAKEN SERIES: 3) Frequency-Dependent Foraging [#permalink]

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New post 05 Jun 2015, 21:50
apoorv601 wrote:
Hi Max,
Good to see ur post!!

Conclusion - The varying results must have been attributable to quality of the way the experiments were maintained by the researchers conducting them
Premise - Generally, the more populous a species, the more likely that species is to be selected as the primary foraged species; several unrelated university sponsored laboratory experiments on bumblebees, tested with an identical foraged species, yielded dramatically different results. In some experiments, the bumblebees thrived, while in others they perished.

The argument in the conclusion assumes a cause for the difference in results of an experiment. The things that can weaker the conclusion might be alternate causes of the conclusion, new fact that undermine the quoted cause, etc.

Ⓐ In the wild, frequency-dependent foraging among bumblebees typically occurs when any one of a small number of foraged species is present. - This if true would result in no foraging of bumblebees at all while we see from the experiment that foraging occurs in some cases and did not occur at other.

Ⓑ The same basic experiment design guidelines were used for each of the experiments. - This doesn't undermine the conclusion, while the same basic guidelines may have been used in experiment but the quality of the way the experiments were maintained by the researchers conducting them could have varied, resulting in the difference in results.

Ⓒ The number of academic calendar years of experience among those who conducted the laboratory experiments varied from four years to five years. - This statement does not help explain the difference in results; while it could be that the experience of the people conducting the research could be different but the difference in results could still be because of the quality of the of the way the experiments were maintained by the researchers conducting them

Ⓓ The species of bumblebee used in the laboratory experiments varied from experiment to experiment. - This would be the perfect answer, this presents and alternate cause to the results; if different species are used in the experiments then the difference in foraging would be dependent on the relative frequency of that foraged species

Ⓔ A team at the same university that conducted one of the frequency-dependent foraging experiments has been accused of exaggerating the findings of an experiment conducted just two years prior. - The question is about the difference in results and not that the results were exaggerated


Hi apoorv601,

Nice to see your response! Nice breakdown as well. There's just one thing I'd like to explore with you a little bit further, and it has to do with options A, and D:

Ⓐ In the wild, frequency-dependent foraging among bumblebees typically occurs when any one of a small number of foraged species is present.

apoorv601 wrote:
This if true would result in no foraging of bumblebees at all while we see from the experiment that foraging occurs in some cases and did not occur at other.


From the prompt, it's not the bumblebees that are BEING FORAGED, but rather that they ARE FORAGING on another species. The experiments are measuring bumblebee behavior, foraging on another species (presumably a species of flower). The way you described A ("foraging of bumblebees"), it reads as though the bumblebees are being devoured.

Than, Ⓓ The species of bumblebee used in the laboratory experiments varied from experiment to experiment.

apoorv601 wrote:
This would be the perfect answer, this presents and alternate cause to the results; if different species are used in the experiments then the difference in foraging would be dependent on the relative frequency of that foraged species


In saying "This would be the perfect answer, this presents and alternate cause to the results", that's exactly right.

However there's something to explore in what follows: "if different species are used in the experiments then the difference in foraging would be dependent on the relative frequency of that foraged species". The foraged species (the one being foraged on by the bumblebees) is the same. According to D, we're being told that the bumblebee species varied. That's how it weakens. Different species of bumblebee, could react very differently to the same foraged species.

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The reason why I wanted to point that out is that sometimes those key conceptual relationships can have big payouts in both CR and RC. If you can read especially carefully when a key relationship is being described, you'll be rewarded. We see that over and over again in official prompts and passages.
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Re: CR WEAKEN SERIES: 3) Frequency-Dependent Foraging [#permalink]

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Patronus wrote:
Premise:
More populous species = more likely it is selected to be primary foraged species

Conclusion:
ONLY the way the experiments were conducted => varying results (C => E)

Weakener:
What if some other cause resulted in this effect? (Classic trap)
For example: What if areas where more B were killed had more B to start with? And areas where less B were killed had less B to start with?
This can ALSO explain the effect in the conclusion. So, the given conclusion is NOT the ONLY reason why the effect happened.


Ⓐ In the wild, frequency-dependent foraging among bumblebees typically occurs when any one of a small number of foraged species is present. - We have to attack the conclusion, which is based on experiments performed and NOT based in wild.
Ⓑ The same basic experiment design guidelines were used for each of the experiments. -
Great, this will strengthen the conclusion because it removes the doubt that any experiment had more favorable factors than others. Basically this choice says the sample is representative of the whole.
Ⓒ The number of academic calendar years of experience among those who conducted the laboratory experiments varied from four years to five years.
Assume for a while that this choice does matter. Then we have to assume that the experience of guys somehow has the effect on the understanding of the results. But we are not given if 4-5years of experience has +ve or -ve effect on the understanding of the results (!)
Ⓓ The species of bumblebee used in the laboratory experiments varied from experiment to experiment.
Aha! This choice means that there was atleast SOME other factor that was variable in all these experiments that was ALSO responsible for "varying results", our conclusion.
Ⓔ A team at the same university that conducted one of the frequency-dependent foraging experiments has been accused of exaggerating the findings of an experiment conducted just two years prior.
Assume for a while that this choice were true. Then we have to assume that because they were accussed 2 YEARS PRIOR, means they will ALSO manipulate the results now. Don't know for sure.

Answer choice D is correct based on weakener pre-thought earlier.


Great breakdown Patronus! Your logic is spot on all the way through. I especially like your breakdowns for options C and E.
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Re: CR WEAKEN SERIES: 3) Frequency-Dependent Foraging [#permalink]

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New post 05 Jun 2015, 22:11
Engr2012 wrote:
CR WEAKEN SERIES: 3) Frequency-Dependent Foraging

Frequency-dependent foraging refers to the tendency of an individual to selectively forage on a certain species based on the relative frequency of that foraged species in the wild. Generally, the more populous a species, the more likely that species is to be selected as the primary foraged species. Surprisingly, several unrelated university sponsored laboratory experiments on bumblebees, tested with an identical foraged species, yielded dramatically different results. In some experiments, the bumblebees thrived, while in others they perished. Given that each of the experiments had comparable funding, the varying results must have been attributable to the quality of the way the experiments were maintained by the researchers conducting them.

Text in green: Premises/background.
Text in Red: Conclusion

The conclusion states that there is only 1 reason for the variation in results presented by the 2 university experiments and this reason is the quality of the way the experiments were mainitained by the researchers conducting them.

Prethinking process : As this is a weakener question, the correct answer choice will weaken the conclusion by mentioning about an alternate reasoning with a high possibility. Choice D does exactly that.

Which one of the following, if true, casts the most doubt on the conclusion drawn above?

Ⓐ In the wild, frequency-dependent foraging among bumblebees typically occurs when any one of a small number of foraged species is present.
Incorrect. Irrelevant. This option talks about the species in the wild.

Ⓑ The same basic experiment design guidelines were used for each of the experiments.
Incorrect. This choice strengthens the conclusion that the quality alone was the reason for the difference in the results.

Ⓒ The number of academic calendar years of experience among those who conducted the laboratory experiments varied from four years to five years.
Incorrect: Irrelevant. Number of years of experience is not important.

Ⓓ The species of bumblebee used in the laboratory experiments varied from experiment to experiment.
Correct. As explained in the prethinking process above. I do have a question though. How is this option correct when the premise says that the foraged species used in the experiment were identical? In GMAT, I have not seen CR arguments that attack the premises. Premises must be considered true in GMAT.

Ⓔ A team at the same university that conducted one of the frequency-dependent foraging experiments has been accused of exaggerating the findings of an experiment conducted just two years prior.
Incorrect. It might mean that the university teams have a propensity to exaggerate their findings. If anything, this choice will be equally applicable to both the research teams and as such would not harm the conclusion. If this option would have provided some sort of evidence to justify why 1 of the 2 teams would exaggerate its results, then this option could have been taken into account.


Hi Engr2012,

Nice breakdown as well! Two things to discuss:

1) To the question you raised in your discussion of option D) It sounds like you're confusing the two parties of the experiments: The forager (the bumblebees), and The Foraged Species (a flower, for example).

The prompt says that THE FORAGED SPECIES is the same. Option D says the the FORAGER SPECIES varied. Therefore, the option does not run counter to the prompt, and you are correct in your awareness that correct official GMAT weakener options don't attack the facts of the prompt, but rather the underlying logic.

2) More of a minor aside that's worth pointing out because it could have an impact with an Inference Question (typically 6 per GMAT between RC and CR, so this could be a high impact thing to point out!): You said:

Engr2012 wrote:
The conclusion states that there is only 1 reason for the variation in results presented by the 2 university experiments and this reason is the quality of the way the experiments were mainitained by the researchers conducting them.

Just because we have two different stated outcomes (some bumblebees thriving, and others perishing), can we infer that there are 2 university experiments? No. There could have been 3, dozens, or even more. The results described only describe the range. The actual results could have happened anywhere within and including that described range (some bumblebees thriving, some doing just okay, and others perishing).

As another example of the inferential logic here, let's say that we're told that in a road test, one car had a 0-60 time of 2.9, and another 12.2. Can we infer that they only tested 2 cars? No. Since we're only being told the range, and nothing else, there's no way to deduce the number of cars.

We can, however, infer that there ARE AT LEAST 2 CARS involved in the test.

The same would apply to the range of results described in the bumblebee experiments.
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Re: CR WEAKEN SERIES: 3) Frequency-Dependent Foraging [#permalink]

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New post 05 Jun 2015, 22:15
EMPOWERgmatMax wrote:
apoorv601 wrote:
Hi Max,
Good to see ur post!!

Conclusion - The varying results must have been attributable to quality of the way the experiments were maintained by the researchers conducting them
Premise - Generally, the more populous a species, the more likely that species is to be selected as the primary foraged species; several unrelated university sponsored laboratory experiments on bumblebees, tested with an identical foraged species, yielded dramatically different results. In some experiments, the bumblebees thrived, while in others they perished.

The argument in the conclusion assumes a cause for the difference in results of an experiment. The things that can weaker the conclusion might be alternate causes of the conclusion, new fact that undermine the quoted cause, etc.

Ⓐ In the wild, frequency-dependent foraging among bumblebees typically occurs when any one of a small number of foraged species is present. - This if true would result in no foraging of bumblebees at all while we see from the experiment that foraging occurs in some cases and did not occur at other.

Ⓑ The same basic experiment design guidelines were used for each of the experiments. - This doesn't undermine the conclusion, while the same basic guidelines may have been used in experiment but the quality of the way the experiments were maintained by the researchers conducting them could have varied, resulting in the difference in results.

Ⓒ The number of academic calendar years of experience among those who conducted the laboratory experiments varied from four years to five years. - This statement does not help explain the difference in results; while it could be that the experience of the people conducting the research could be different but the difference in results could still be because of the quality of the of the way the experiments were maintained by the researchers conducting them

Ⓓ The species of bumblebee used in the laboratory experiments varied from experiment to experiment. - This would be the perfect answer, this presents and alternate cause to the results; if different species are used in the experiments then the difference in foraging would be dependent on the relative frequency of that foraged species

Ⓔ A team at the same university that conducted one of the frequency-dependent foraging experiments has been accused of exaggerating the findings of an experiment conducted just two years prior. - The question is about the difference in results and not that the results were exaggerated


Hi apoorv601,

Nice to see your response! Nice breakdown as well. There's just one thing I'd like to explore with you a little bit further, and it has to do with options A, and D:

Ⓐ In the wild, frequency-dependent foraging among bumblebees typically occurs when any one of a small number of foraged species is present.

apoorv601 wrote:
This if true would result in no foraging of bumblebees at all while we see from the experiment that foraging occurs in some cases and did not occur at other.


From the prompt, it's not the bumblebees that are BEING FORAGED, but rather that they ARE FORAGING on another species. The experiments are measuring bumblebee behavior, foraging on another species (presumably a species of flower). The way you described A ("foraging of bumblebees"), it reads as though the bumblebees are being devoured.

Than, Ⓓ The species of bumblebee used in the laboratory experiments varied from experiment to experiment.

apoorv601 wrote:
This would be the perfect answer, this presents and alternate cause to the results; if different species are used in the experiments then the difference in foraging would be dependent on the relative frequency of that foraged species


In saying "This would be the perfect answer, this presents and alternate cause to the results", that's exactly right.

However there's something to explore in what follows: "if different species are used in the experiments then the difference in foraging would be dependent on the relative frequency of that foraged species". The foraged species (the one being foraged on by the bumblebees) is the same. According to D, we're being told that the bumblebee species varied. That's how it weakens. Different species of bumblebee, could react very differently to the same foraged species.

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The reason why I wanted to point that out is that sometimes those key conceptual relationships can have big payouts in both CR and RC. If you can read especially carefully when a key relationship is being described, you'll be rewarded. We see that over and over again in official prompts and passages.


Thanks for the clarification max!!
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Re: CR WEAKEN SERIES: 3) Frequency-Dependent Foraging [#permalink]

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New post 06 Jun 2015, 01:38
EMPOWERgmatMax wrote:
Engr2012 wrote:
CR WEAKEN SERIES: 3) Frequency-Dependent Foraging

Frequency-dependent foraging refers to the tendency of an individual to selectively forage on a certain species based on the relative frequency of that foraged species in the wild. Generally, the more populous a species, the more likely that species is to be selected as the primary foraged species. Surprisingly, several unrelated university sponsored laboratory experiments on bumblebees, tested with an identical foraged species, yielded dramatically different results. In some experiments, the bumblebees thrived, while in others they perished. Given that each of the experiments had comparable funding, the varying results must have been attributable to the quality of the way the experiments were maintained by the researchers conducting them.

Text in green: Premises/background.
Text in Red: Conclusion

The conclusion states that there is only 1 reason for the variation in results presented by the 2 university experiments and this reason is the quality of the way the experiments were mainitained by the researchers conducting them.

Prethinking process : As this is a weakener question, the correct answer choice will weaken the conclusion by mentioning about an alternate reasoning with a high possibility. Choice D does exactly that.

Which one of the following, if true, casts the most doubt on the conclusion drawn above?

Ⓐ In the wild, frequency-dependent foraging among bumblebees typically occurs when any one of a small number of foraged species is present.
Incorrect. Irrelevant. This option talks about the species in the wild.

Ⓑ The same basic experiment design guidelines were used for each of the experiments.
Incorrect. This choice strengthens the conclusion that the quality alone was the reason for the difference in the results.

Ⓒ The number of academic calendar years of experience among those who conducted the laboratory experiments varied from four years to five years.
Incorrect: Irrelevant. Number of years of experience is not important.

Ⓓ The species of bumblebee used in the laboratory experiments varied from experiment to experiment.
Correct. As explained in the prethinking process above. I do have a question though. How is this option correct when the premise says that the foraged species used in the experiment were identical? In GMAT, I have not seen CR arguments that attack the premises. Premises must be considered true in GMAT.

Ⓔ A team at the same university that conducted one of the frequency-dependent foraging experiments has been accused of exaggerating the findings of an experiment conducted just two years prior.
Incorrect. It might mean that the university teams have a propensity to exaggerate their findings. If anything, this choice will be equally applicable to both the research teams and as such would not harm the conclusion. If this option would have provided some sort of evidence to justify why 1 of the 2 teams would exaggerate its results, then this option could have been taken into account.


Hi Engr2012,

Nice breakdown as well! Two things to discuss:

1) To the question you raised in your discussion of option D) It sounds like you're confusing the two parties of the experiments: The forager (the bumblebees), and The Foraged Species (a flower, for example).

The prompt says that THE FORAGED SPECIES is the same. Option D says the the FORAGER SPECIES varied. Therefore, the option does not run counter to the prompt, and you are correct in your awareness that correct official GMAT weakener options don't attack the facts of the prompt, but rather the underlying logic.

2) More of a minor aside that's worth pointing out because it could have an impact with an Inference Question (typically 6 per GMAT between RC and CR, so this could be a high impact thing to point out!): You said:

Engr2012 wrote:
The conclusion states that there is only 1 reason for the variation in results presented by the 2 university experiments and this reason is the quality of the way the experiments were mainitained by the researchers conducting them.

Just because we have two different stated outcomes (some bumblebees thriving, and others perishing), can we infer that there are 2 university experiments? No. There could have been 3, dozens, or even more. The results described only describe the range. The actual results could have happened anywhere within and including that described range (some bumblebees thriving, some doing just okay, and others perishing).

As another example of the inferential logic here, let's say that we're told that in a road test, one car had a 0-60 time of 2.9, and another 12.2. Can we infer that they only tested 2 cars? No. Since we're only being told the range, and nothing else, there's no way to deduce the number of cars.

We can, however, infer that there ARE AT LEAST 2 CARS involved in the test.

The same would apply to the range of results described in the bumblebee experiments.


Hi Max

Thanks for the explanation. Yes you are correct about the incorrect wording of my option there. I'll be a bit more careful with my explanations.
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Re: CR WEAKEN SERIES: 3) Frequency-Dependent Foraging [#permalink]

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Re: CR WEAKEN SERIES: 3) Frequency-Dependent Foraging [#permalink]

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New post 18 Sep 2017, 05:42
Good question

Concl - > Difference in Quality of experiments --> difference in results.

Option D: Alternative conclusion
Difference in subjects (Bumblebees) --> difference in results.
Re: CR WEAKEN SERIES: 3) Frequency-Dependent Foraging   [#permalink] 18 Sep 2017, 05:42
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