生物统计学中的常规统计测验方法,一般都是假设其总体是服从正态分布或接近正态分布为前提的.但是随着科研领域的扩大和考察问题的深入,有些研究因总体分布的性质和形状缺乏了解,甚至属于无特定分布的总体,因此,在一般情况下就无法取得总体参数.适合这类资料的统计方法称作非参量统计(nonparametric statisti??s)、这类统计方法的优点是计算量小,易于掌握和应用. Conventional statistical test methods in biostatistics generally assume that the overall statistic is based on the normal distribution or near normal distribution.But with the expansion of the field of scientific research and study problems, some studies due to the nature of the overall distribution And lack of understanding of the shape, and even the population as a whole without any specific distribution, the general parameters can not be obtained in general. Statistical methods suitable for this type of data are called nonparametric statistizes. The advantage is a small amount of calculation, easy to grasp and application.