LR Question 20 Explanation
QUESTION TEXT: Geologist: A new method for forecasting earthquakes has …
QUESTION TYPE: Sufficient Assumption
CONCLUSION: The new earthquake-forecasting model is unlikely to be useful.
REASONING: It predicts earthquakes within a range of 2.5 points on the Richter scale. This difference can range from minor tremors to highly destructive earthquakes, so it’s too imprecise.
ANALYSIS: The argument assumes that a method is not useful unless it can distinguish between minor and destructive earthquakes. But it hasn’t actually established this. What if a method is useful so long as it can reliably predict that an earthquake will happen? The new method has done this. So if this were the case, the conclusion wouldn’t logically follow.
Thus, the correct answer will bridge this gap by explicitly stating that an earthquake-forecasting method must differentiate between low-impact and high-impact earthquakes in order to be useful. Or that it must be precise on the Richter scale.
___________
- This states that a method must be reliable, but the argument already accepts that the method is reliable – it just isn’t precise enough. Reliability isn’t the missing link.
- CORRECT. This directly links usefulness and the ability to differentiate between minor and destructive earthquakes. If a method must provide this distinction to be useful, then the geologist’s conclusion logically follows.
- The argument isn’t about how many earthquakes the method has predicted but rather how precise these predictions are. From what we know, a method could be useful after only a few predictions if they were precise enough.
- Even if other forecasting methods exist with narrow ranges, this doesn’t explain why the new method itself must be precise to be useful. The argument is about this specific method and why it’s inadequate, not how it compares to others.
- This is very close, but it’s too weak. E says the method will probably be of little use, while the geologist’s conclusion is definitive.
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