Critical Reasoning

Q32:
A major chemical spill occurred five years ago at Baker’s Beach, the world’s sole nesting ground for Merrick sea turtles, and prevented nearly all the eggs laid that year from hatching. Yet the number of adult female Merricks returning to lay their eggs at Baker’s Beach has actually increased somewhat since five years ago. Clearly, environmentalists’ prediction that the world’s Merrick population would decline as a result of the spill has proven unfounded.
Which of the following, if true, most seriously undermines the argument offered in refutation of the environmentalists’ prediction?

A. The chemical spill five years ago occurred at a time when there were neither Merrick sea turtles nor Merrick sea turtle eggs on Baker’s Beach.
B. Female Merrick sea turtles begin returning to Baker’s Beach to lay their eggs when they are ten years old.
C. Under normal conditions, only a small proportion of hatchling female Merrick sea turtles survive in the ocean until adulthood and return to lay their eggs at Baker’s Beach.
D. Environmental pressures unrelated to the chemical spill have caused a significant decline in the population of one of the several species of sea birds that prey on Merrick sea turtle eggs.
E. After the chemical spill, an environmental group rejected a proposal to increase the Merrick sea turtle population by transferring eggs from Baker’s Beach to nearby beaches that had not been affected by the spill.

(B)

I would go with A.
I ve seen question somewhere.

showbu wrote:Q32:
A major chemical spill occurred five years ago at Baker’s Beach, the world’s sole nesting ground for Merrick sea turtles, and prevented nearly all the eggs laid that year from hatching. Yet the number of adult female Merricks returning to lay their eggs at Baker’s Beach has actually increased somewhat since five years ago. Clearly, environmentalists’ prediction that the world’s Merrick population would decline as a result of the spill has proven unfounded.
Which of the following, if true, most seriously undermines the argument offered in refutation of the environmentalists’ prediction?

A. The chemical spill five years ago occurred at a time when there were neither Merrick sea turtles nor Merrick sea turtle eggs on Baker’s Beach.
B. Female Merrick sea turtles begin returning to Baker’s Beach to lay their eggs when they are ten years old.
C. Under normal conditions, only a small proportion of hatchling female Merrick sea turtles survive in the ocean until adulthood and return to lay their eggs at Baker’s Beach.
D. Environmental pressures unrelated to the chemical spill have caused a significant decline in the population of one of the several species of sea birds that prey on Merrick sea turtle eggs.
E. After the chemical spill, an environmental group rejected a proposal to increase the Merrick sea turtle population by transferring eggs from Baker’s Beach to nearby beaches that had not been affected by the spill.

OA Spoiler Code B

showbu wrote:Q32:
A major chemical spill occurred five years ago at Baker’s Beach, the world’s sole nesting ground for Merrick sea turtles, and prevented nearly all the eggs laid that year from hatching. Yet the number of adult female Merricks returning to lay their eggs at Baker’s Beach has actually increased somewhat since five years ago. Clearly, environmentalists’ prediction that the world’s Merrick population would decline as a result of the spill has proven unfounded.
Which of the following, if true, most seriously undermines the argument offered in refutation of the environmentalists’ prediction?

A. The chemical spill five years ago occurred at a time when there were neither Merrick sea turtles nor Merrick sea turtle eggs on Baker’s Beach.
B. Female Merrick sea turtles begin returning to Baker’s Beach to lay their eggs when they are ten years old.
C. Under normal conditions, only a small proportion of hatchling female Merrick sea turtles survive in the ocean until adulthood and return to lay their eggs at Baker’s Beach.
D. Environmental pressures unrelated to the chemical spill have caused a significant decline in the population of one of the several species of sea birds that prey on Merrick sea turtle eggs.
E. After the chemical spill, an environmental group rejected a proposal to increase the Merrick sea turtle population by transferring eggs from Baker’s Beach to nearby beaches that had not been affected by the spill.

For a weakening question, we want to cast doubt on the author's conclusion.

The author concludes that the environmentalists are wrong, i.e. that the number of turtles will decline as a result of the spill is incorrect. The author bases this on the number of females who returned this year, 5 years after the spill, is higher than previous years.

One great way to weaken is to show that the author's evidence is irrelevant to the author's conclusion. Choice (B) does exactly that.

If it takes 10 years for turtles to mature to egg laying status, then looking at numbers only 5 years after the spill is irrelevant. Since (B) renders the author's evidence irrelevant, it weakens the author's conclusion.

Stuart Kovinsky wrote:

showbu wrote:Q32:
A major chemical spill occurred five years ago at Baker�s Beach, the world�s sole nesting ground for Merrick sea turtles, and prevented nearly all the eggs laid that year from hatching. Yet the number of adult female Merricks returning to lay their eggs at Baker�s Beach has actually increased somewhat since five years ago. Clearly, environmentalists� prediction that the world�s Merrick population would decline as a result of the spill has proven unfounded.
Which of the following, if true, most seriously undermines the argument offered in refutation of the environmentalists� prediction?

A. The chemical spill five years ago occurred at a time when there were neither Merrick sea turtles nor Merrick sea turtle eggs on Baker�s Beach.
B. Female Merrick sea turtles begin returning to Baker�s Beach to lay their eggs when they are ten years old.
C. Under normal conditions, only a small proportion of hatchling female Merrick sea turtles survive in the ocean until adulthood and return to lay their eggs at Baker�s Beach.
D. Environmental pressures unrelated to the chemical spill have caused a significant decline in the population of one of the several species of sea birds that prey on Merrick sea turtle eggs.
E. After the chemical spill, an environmental group rejected a proposal to increase the Merrick sea turtle population by transferring eggs from Baker�s Beach to nearby beaches that had not been affected by the spill.

For a weakening question, we want to cast doubt on the author's conclusion.

The author concludes that the environmentalists are wrong, i.e. that the number of turtles will decline as a result of the spill is incorrect. The author bases this on the number of females who returned this year, 5 years after the spill, is higher than previous years.

One great way to weaken is to show that the author's evidence is irrelevant to the author's conclusion. Choice (B) does exactly that.

If it takes 10 years for turtles to mature to egg laying status, then looking at numbers only 5 years after the spill is irrelevant. Since (B) renders the author's evidence irrelevant, it weakens the author's conclusion.

Can you explain more why other choices is wrong. I choose (D) although I feel other choices very temping. Thanks

tuanquang269 wrote:

Stuart Kovinsky wrote:

showbu wrote:Q32:
A major chemical spill occurred five years ago at Baker�s Beach, the world�s sole nesting ground for Merrick sea turtles, and prevented nearly all the eggs laid that year from hatching. Yet the number of adult female Merricks returning to lay their eggs at Baker�s Beach has actually increased somewhat since five years ago. Clearly, environmentalists� prediction that the world�s Merrick population would decline as a result of the spill has proven unfounded.
Which of the following, if true, most seriously undermines the argument offered in refutation of the environmentalists� prediction?

A. The chemical spill five years ago occurred at a time when there were neither Merrick sea turtles nor Merrick sea turtle eggs on Baker�s Beach.
B. Female Merrick sea turtles begin returning to Baker�s Beach to lay their eggs when they are ten years old.
C. Under normal conditions, only a small proportion of hatchling female Merrick sea turtles survive in the ocean until adulthood and return to lay their eggs at Baker�s Beach.
D. Environmental pressures unrelated to the chemical spill have caused a significant decline in the population of one of the several species of sea birds that prey on Merrick sea turtle eggs.
E. After the chemical spill, an environmental group rejected a proposal to increase the Merrick sea turtle population by transferring eggs from Baker�s Beach to nearby beaches that had not been affected by the spill.

For a weakening question, we want to cast doubt on the author's conclusion.

The author concludes that the environmentalists are wrong, i.e. that the number of turtles will decline as a result of the spill is incorrect. The author bases this on the number of females who returned this year, 5 years after the spill, is higher than previous years.

One great way to weaken is to show that the author's evidence is irrelevant to the author's conclusion. Choice (B) does exactly that.

If it takes 10 years for turtles to mature to egg laying status, then looking at numbers only 5 years after the spill is irrelevant. Since (B) renders the author's evidence irrelevant, it weakens the author's conclusion.

Can you explain more why other choices is wrong. I choose (D) although I feel other choices very temping. Thanks

Even i will go with D.
Reason-
Concl - X hapnes because of Y.
D simply states - Return of turtles is due to Z, which is not Y.
Hence D.

pdsrocks wrote: Even i will go with D.
Reason-
Concl - X hapnes because of Y.
D simply states - Return of turtles is due to Z, which is not Y.
Hence D.

Almost if not every option is possible. A problem routinely seen by 'trained' decisions makers who learn that every honest answer must include numbers and underlying facts. Invent missing numbers to make any reply possible.

For example, the reproduction cycle time can be more than 5 years. Record high reproduction occurred every year before the spill. Environmental conditions (ie sudden elimination of predators) have also changed so that virtually no turtles die over many years. Or the number of turtles that return to reproduce increases when fewer turtles are found at sea. Any might explain why more turtles return to reproduce. Some numbers say why the environmentalists were correct. But what is most obvious: any conclusion only from those observations is classic junk science reasoning.

Best answer is that experts must be taken at their word because we layman are missing the most important facts and numbers. Which, BTW, is how propaganda works.

A similar example is the corporate spread sheet. Innovation take four to ten years to create profits. Those who make judgments based upon a decade of spread sheets will see innovators as a company's greatest asset. Those who judge based upon annual profit reports will label those same innovators as an expense that must be cost controlled. Two 180 degree different conclusions because some fail to learn critical numbers and an economic fact.

Innovation typically takes four to ten years before a spread sheet can quantify resulting profits. The most easily deceived will see massive profits next year because all R&D was terminated. That proves R&D harms profits? Yes, if only using observation. Turtles, with five year reproduction cycles, means anyone making conclusions only from observation is making the same junk science mistake.

(B)

so all these female turtles were born before the spill..not after

ArunangsuSahu wrote:so all these female turtles were born before the spill..not after

We don't know. Because critical facts must include numbers. No numbers (other than years) are provided. Critical thinking is impossible without perspective. That means numbers. Subjective reasoning is often called junk science.

Great insight and analogy provided by @Westom. We need to remember that CR is modeled on critical thinking in real world situation. I think the kind of reasoning employed above would be the same, if we imagine ourselves to be on the shoreline and contemplating on what might be the reason(s) of increased females returning to the shores, in spite of the potential hazard to the new hatchlings. If we were the environmentalists analyzing (decades of data on the reproduction cycle of turtles -choice (B) would definitely weaken the conclusion by the author. The Most probable thinking in this situation would be that "Majority of females coming for the first time to lay eggs, still didn't complete their reproductive cycle". Although there could be female turtles (who already reached their reproductive stage of laying eggs), but this assumption is not as probable as the earlier one. SO the best answer here could be (B).

Note here that (D) is not weakening the conclusion, in fact it's strengthening the author's contention. Author says that prediction of the environmentalist's prediction is unfounded. We need to weaken this conclusion. The most apt weakener would be if we could show that the prediction and concerns are not unfounded or futile. (D) saying that the decline was due to other environmental reasons and not the spill of oil, strengthens this fact that prediction is indeed unfounded.

An alternative cause can weaken a conclusion, only if the conclusion says that the effect was solely caused by X. However here the conclusion is different. No such connotation of "only X" is implied in the conclusion.

Thanks
Prashant