临床实验研究通过试验因素（处理因素）作用于受试对象所出现的反应（效应）来验证假说 ,回答、解决实验研究课题 ;然而受试对象表现出的效应 ,并不完全是处理因素单独作用的结果 ,试验过程中伴随的混杂因素同样作用于受试对象而产生效应。正因为受试对象表现出来的效应 ,是处? Clinical trial studies validate the hypothesis by answering the responses (effects) that the test factor (treatment factor) acts on the test subject, answering and solving the experimental research topic; however, the effect exhibited by the test subject is not entirely the effect of the treatment factor alone The results, the confounding factors associated with the test process the same effect on the test subjects. It is precisely because the subjects showed the effect is at?