搞临床研究的目的在于探求适用于全体的客观规律。而研究的对象,仅能是全体中的小部分,这一小部分称为样本,样本所代表的全体称为总体。因为研究样本的目的是要推论总体,所以样本必须具有代表性,否则,就不能正确地推论总体。这些概念本来是容易理解的,但在当前临床医学研究中,特别是对新疗法的评价中,忽视样本代表性的现象却比较多见。为此,本文从卫生统计 The purpose of clinical research is to explore the objective laws applicable to all. The study of the object, only a small part of the whole, this small part called the sample, the sample represented by the overall known as the overall. Because the purpose of the study sample is to infer the population, the sample must be representative, otherwise the population can not be correctly inferred. These concepts were originally understandable, but in current clinical research, especially in the evaluation of new therapies, it is more common to ignore sample representativeness. To this end, this article from the health statistics