I finally found an instruction from lawyer: "一。ASSUMPTION类。假设类分充分型和必要型。充分型是问题问你下列哪个假设，能使原文的结论PROPOERLY推出。必要型是问题问你原文的推理依赖下列哪个假设。他们的作题思路不同。充分类因为原文结论是必须能从证据推出（加上假设），所以方法较简单，将选项加到原文的推理中，如果结论必成立（MUST BE），则为答案，如果结论有不成立的可能性，则错，其中的特例是原文证据和结论的概念差异（GAP），说出这个GAP就是假设。必要类复杂点，总体的方法是将选项取非，如果原文的结论必不成立，则为答案，如果还有成立的可能性，则错。取非就是假设选项是错的。其中有几种特例。一是其他类（其他原因，可能性。。。），它的假设是不存在其他（原因，可能）。另一种是原文证据和结论的概念差异（GAP），说出这个差异就是假设。还有一种是只考虑单方面，其假设是其他方面没影响。其特例是比较两个东东，只比较某方面，便得出一个总体结论，其假设是其他方面没影响。充分类的加进法和必要类的取非法都可用于TEST所有选项，但因时间较长，所以通常方法是用有关无关排除后剩下难分的选项才用这方法，很多情况下通过有关无关排除便只剩下一个。他们的特例则可以直接找答案。"
As I said, I think CR 78 belongs to 必要型.
The next question is, how to differentiate 充分型 and 必要型?
Show me your reasoning why after negating A, the argument might not hold.
Remember, no outside assumptions or opinions. Just follow the logic presented in the stimulus.
-- by 会员 sdcar2010 (2011/3/6 1:59:04)
Say, we have 100 drivers, 3 of them equipped their vehicles with radar detectors (we call them RD), and 97 did not (we call them NRD). Each driver drives exceeding the speed limite 11 times during the report period. As we negating A, RD are more likely to be tiketed than NRD, so it is possible that the 11 times for the 3 RD are all tiketed, while the 11 times for the 97 NRD are only ticketed for 67 times in total. Then the report showed that 33% tiketed vehicles are all equipped with radar detector. Under this condition, we cannot get the conclusion that RD are more likely to exceed the speed limit regularly than NRD, since the times they do during a certain period are the same.
This is an extreme example, though. But we can see from this that the conclusion "might" not hold. This is also why I said, without the assumption the question is asking, the argument itself is not logical.
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Show me your reasoning why after negating A, the argument might not hold.<br /><br />Remember, no outside assumptions or opinions. Just follow the logic presented in the stimulus.<div style="text-align:right;">-- by 会员 <u>sdcar2010</u> (2011/3/6 1:59:04)</div><br /><br /><br /><br /><br />
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<br /><br />Say, we have 100 drivers, 3 of them equipped their vehicles with radar detectors (we call them RD), and 97 did not (we call them NRD). Each driver drives exceeding the speed limite 11 times during the report period. As we negating A, RD are more likely to be tiketed than NRD, so it is possible that the 11 times for the 3 RD are all tiketed, while the 11 times for the 97 NRD are only ticketed for 67 times in total. Then the report showed that 33% tiketed vehicles are all equipped with radar detector. Under this condition, we cannot get the conclusion that RD are more likely to exceed the speed limit regularly than NRD, since the times they do during a certain period are the same.<br /><br />This is an extreme example, though. But we can see from this that the conclusion "might" not hold.<br />This is also why I said, without the assumption the question is asking, the argument itself is not logical.<div style="text-align:right;">-- by 会员 <u>nightingale</u> (2011/3/6 9:18:20)</div><br />
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Interesting example. However, it is not what the stimulus describes. First, the stimulus talks about vehicles, not drivers. Second when it says 33% of the ticketed vechiles are equipped with RD, it means 100 different vehicles, not the same car being ticketed over and over.
Oh, LS, use greaterer numbers, 300 RD and 9700 NRD with one exceed each. Still, 33 of RD and 67 of NRD are ticketed. Then we can solve the "over and over" problem.
The theme here is that the conclusion might not hold.
Oh, LS, use greaterer numbers, 300 RD and 9700 NRD with one exceed each. Still, 33 of RD and 67 of NRD are ticketed. Then we can solve the "over and over" problem.
The theme here is that the conclusion might not hold.
-- by 会员 nightingale (2011/3/6 15:39:42)
First, your example is wrong, again, because you used the following premise/assumption: Both RD and NRD has the same rate of exceeding speed limit. The stimulus never says that.
Second, if you start with this "equal rate" premise/assumption, of course you will reach a different conclusion from that of the stimulus because you already set the conclusion you want to reach in your premise/assumption. This is akin to circular reasoning.
It is not my premise/assumption. It is just an example of possible condition to show that when the premises of the questions are met (3% and 33%), the conclusion (more regularly) might not hold.
As I said, I already know the difference between A and B, based on lawyer's theory. It is just another question I need to figure out: when the question is 充分型, and when it is 必要型. If you would like, we can move on.
"300 RD and 9700 NRD with one exceed each" That is an additional premise on top of the 3% and 33% premises provided by the author. Therefore, it is an outside info which is not allowed in CR question.
As to "when the question is 充分型, and when it is 必要型.", the former is justifying assumption while the latter is necessargy assumption.
Necessary: depend on, rely on, need, require, must-be-true.
For a necessary assumption question, the correct answer is the one that is necessary for the conclusion to be drawn or to depend on: the conclusion of the stimulus cannot be drawn without it; but at the same time, the necessary assumption alone is not enough to bring about the conclusion of the stimulus.
As to justifying assumption questions, the correct answer is the one that is sufficient for the conclusion to be drawn: the answer choice itself is enough to lead to the conclusion; but the correct answer choice does not necessarily have to be the ONLY case which makes the conclusion righ. That is, there could be other routes for justifying the same conclusion.
As to "when the question is 充分型, and when it is 必要型.", the former is justifying assumption while the latter is necessargy assumption.
Necessary: depend on, rely on, need, require, must-be-true.
-- by 会员 sdcar2010 (2011/3/6 22:57:24)
Thanks very much, sdcar. Do we have any key words for the justifying assumption? or just without the ones for necessary assumption, the question type should be justifying assumption?
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发表于 2011-3-6 12:01:10
