以下是引用fionawyy在2008-9-21 17:38:00的发言：我想再请ＮＮ 们帮我分析以下这题： Q40: Mice that have been given morphine are very likely to develop blood poisoning because bacteria that normally reside in the intestine typically respond to morphine by migrating into the bloodstream. However, when mice are given both morphine and the new drug naltrexone, blood poisoning is much less frequent, although it does still occur. These results provide support for researchers’ prediction that naltrexone will turn out to be toxic to certain types of bacteria. Which of the following, if discovered to be true, would most seriously weaken the support for the researchers’ prediction?
Which of the following, if discovered to be true, would most seriously weaken the support for the researchers’ prediction? After being administered to mice, naltrexone does not pass from the bloodstream into the intestine.
After being administered to mice, naltrexone does not pass from the bloodstream into the intestine. - Naltrexone inhibits morphine from triggering the migration of intestinal bacteria into the bloodstream.
- Mice that have been given naltrexone but not morphine have no greater risk of developing blood poisoning than do mice that have not been given either substance.
- The increased risk of blood poisoning is not the only harmful effect on mice of being given morphine.
- Conditions other than the presence of intestinal bacteria in the bloodstream can cause blood poisoning in mice.
Answer: Ｅ ＷＨＹ？ 就如楼上提醒的，weaken support和weaken prediction 不同。 那这个support是什么呢？为了预测M is toxic to BAC的性能而做的一组实验，Weaken the support 的实质就是质疑实验设计的合理性。我们知道一个实验最好排除一个待研究因素之外的所有因素，其结果才好解释。如果这个实验除了要研究的因素之外还有第二个因素，那么仅仅改变第一个因素而没有限定第二个因素，是没有办法得出的结论的。 B说明实验设计本身没有问题，也就是其结果能解释M的作用机制，虽然其结果实际上就是否定了Prediction，但是没有Weaken support本身。 而E从头否定了实验的意义-----即那一组实验设计没有排除其他因素，其结果没有唯一解释----因此既不存在支持Prediction，也不能否定Prediction --- 从而那个实验是白忙呼 -- weakens the support 欢迎拍砖！ | 
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发表于 2008-9-21 17:38:00
