回归分析中，检验自变量的重要性，将变量一个一个引入引入变量的条件是其偏回归平方和经检验时显著的，在引入新变量的同时，对已入选的变量逐个检验，将不显著的变量剔除。-The importance of the independent variables of regression analysis, test, introducing variable is introduced one by one into the condition of variable is the partial reg

解决逐步回归类问题，包含数据表格以及源代码-Solve the gradual return to the type of problem, including data tables and source code