我也认识是b
并且不觉得牵强啊~~ 第二段强调应该选取更多的人当sample,因为如果只选取特定的人群而又将特殊当普遍A treatment judged successful
under these ideal conditions can then
(30) be evaluated under normal conditions.
那么只有符合被选人群特点的患者接受了successful treamtment!
而e中,如果significant variable 存在,那么risk不能用small形容了吧,我觉得这个选项就是针对文中Frazier and Mosteller contend
that such risk, never entirely eliminable
(15) from research, would still be small in most
studies. 理解得考察~~ |