Q9 - Several major earthquakes have

[john]

9. (D)
Question type: Weaken the conclusion

The argument concludes that the new method of predicting earthquakes, based on electric fluctuations, will help authorities determine the best time to evacuate. If there’s some reason that the new method is not useful for timing evacuations, the argument falls apart. Specifically, if we don’t know how much time will elapse between detecting the fluctuation and the onset of the earthquake, the method won’t tell us the best time to evacuate.

(A) is not relevant; even if the method is not fully understood, it may still serve to help authorities time evacuations.
(B) strengthens the argument; it suggests that the new method is better than most.
(C) raises the irrelevant issue of the increasing frequency of earthquakes.
(E) might sound like a problem: Certainly if there were NO stations that could carry out this method, it wouldn’t be much help, but who says we need more than one?


#officialexplanation

[farhadshekib]

9. (D)
Question type: Weaken the conclusion

The argument concludes that the new method of predicting earthquakes, based on electric fluctuations, will help authorities determine the best time to evacuate. If there’s some reason that the new method is not useful for timing evacuations, the argument falls apart. Specifically, if we don’t know how much time will elapse between detecting the fluctuation and the onset of the earthquake, the method won’t tell us the best time to evacuate.

(A) is not relevant; even if the method is not fully understood, it may still serve to help authorities time evacuations.

(B) strengthens the argument; it suggests that the new method is better than most.
(C) raises the irrelevant issue of the increasing frequency of earthquakes.
(E) might sound like a problem: Certainly if there were NO stations that could carry out this method, it wouldn’t be much help, but who says we need more than one?

I think (A) is referring to a lack of understanding, among the scientific community, with respect to the cause of the changes in the electric currents - and not to a lack of understanding with the "method".

Please correct me if I am wrong, though.

[chike_eze]

I think (A) is referring to a lack of understanding, among the scientific community, with respect to the cause of the changes in the electric currents - and not to a lack of understanding with the "method".

Please correct me if I am wrong, though.

Interesting. However, whether or not Scientists have full understanding is irrelevant. What is relevant is that event A always precedes event B. Therefore, if you detect A, then B will follow. -- who cares why this is the case, it just is.

[maryadkins]

Everyone's right!

I agree that (A) is about the cause of the electric current, not the prediction method. But it's still irrelevant.

Hope this helps.

[ericha3535]

I still don't get how D is correct...

I mean isn't D just saying that there is some gap between length of time between elec and subsequent earthquake?

I don't get how D is saying anything like the scientists don't know anything about the gap?

[aradunakhor]

I have a question about why (A) is wrong: how do we know that all future major earthquakes will be preceded by a change in the electric current in the earth's crust? It could've just been a coincidence that the major earthquakes of the past were preceded by changes in the current. And if scientists don't understand what's bringing about the change then it seems unlikely that they have a good enough understanding to conclude that future major earthquakes will necessarily be preceded by current changes.

[amil91]

I still don't get how D is correct...

I mean isn't D just saying that there is some gap between length of time between elec and subsequent earthquake?

I don't get how D is saying anything like the scientists don't know anything about the gap?

The conclusion of this argument is that the new prediction method will aid local officials in deciding when to evacuate towns for a future earth quake. If the amount of time varies considerably, then this method would not at all be helpful in telling people when to evacuate.

I have a question about why (A) is wrong: how do we know that all future major earthquakes will be preceded by a change in the electric current in the earth's crust? It could've just been a coincidence that the major earthquakes of the past were preceded by changes in the current. And if scientists don't understand what's bringing about the change then it seems unlikely that they have a good enough understanding to conclude that future major earthquakes will necessarily be preceded by current changes.

While I understand where you are coming from in a practical sense, based on what is in the stimulus, this is far too many leaps from what is given, especially in comparison to choice D. The stimulus says, 'several major earthquakes have occurred.... in the last ten years.... 'Detected before each of these were certain changes in the electric current...' This gives us enough evidence that these electrical changes occur every time, regardless of our or the scientists understanding of why the changes occur.

[jeanlouisf]

I still don't get how D is correct...

I mean isn't D just saying that there is some gap between length of time between elec and subsequent earthquake?

I don't get how D is saying anything like the scientists don't know anything about the gap?

Your goal is to weaken the argument. In the most simplest way, the argument is stating that scientist have a new method that helps them know when an earthquake is coming (assuming they have enough time ahead of them before the earthquake occurs) and thus will help local civil defense officials in deciding when to evacuate.

However, if you insert answer D into the mix, what does that do the argument ? Exactly. If there is a number of variations in the length of time between changes in the electric current and the earthquakes that follows the currents, can we say for sure the method will work ? No.

Of all the answer choices, this most weakens the argument.

[christopherr435]

so i have a question to help clarify this question up. after we're given the conclusion, the following sentence tells us that these previous earthquakes were detected by electric current, however, how do we know that this statement applies to the new method the conclusion discusses. meaning how do i know that this detection method will be used amongst the "new prediction method". This part is what confused me in selecting an answer