There is a natural linear order relationship among the data of one - dimensional sample , so which can be ordered according to the size of the sample points , however , since there is no natural linear order relationship among data of multi - dimensional sample , it is impossible to gain multi - dimensional order statistics in accordance with the order of the size of sample , neither is it impossible to extend many useful methods for one - dimensional nonparametric oiatistics to those for high dimensional ones 对于一维样本,由于数据之间存在一种自然的线性序关系,故可按照样本的大小排序,从而得到秩向量。但对于多维样本,数据之间则不存在自然的线性序关系,无法按照样本的大小排序而得到高维样本的次序统计量并由此把一维非参数统计的许多有用的方法直接推广到高维情形,使得对多元数据的统计分析十分麻烦。