A Rank-Sum Testing Method for Multi-Trait Comprehensive Ranking and Its Application

The rank-sum test is a nonparametric method used in variety evaluation. However, the hypothesis testing of the method hasn＇t been established for multi-trait comprehensive ranking. In this paper, under null hypothesis H0： the variety＇s ranking on each trait is random, the theoretical distribution of sum of ranks （SR） was firstly derived and further used to obtain the critical values for multi-trait comprehensive evaluation in rank-sum testing. A new C＋＋ class and its basic arithmetic were defined to deal with the miscount caused by the precision limitation of built-in data type in common statistical software under large number of varieties and traits. Finally, an application of the theoretical results was demonstrated using five starch viscosity traits of 12 glutinous maize varieties. The proposed method is so simple and convenient that it can be easily used to rank different varieties by multiple traits.

多性状综合评定的秩和测验方法及其应用

【目的】秩和比较作为一种非参数方法,虽在作物品种评价方面得到一定的应用,但对多品种多性状的综合评定仍缺乏必要的统计测验基础。【方法】利用"H0:各品种在各性状上的秩次随机分布"假设。【结果】导出了多品种多性状秩和的理论分布;并据之给出了进行品种间多性状综合评价秩和测验的临界值。通过定义任意长度整数C++运算律,解决了当品种数和性状数较多时,因常用软件内置数据类型有效位数不足所导致的计算误差问题。最后,以糯玉米12个品种5个淀粉粘度性状为例演示了分析程序。【结论】该方法操作简便,评定结果具有一定参考意义。