说明：  逐步回归计算源码：从给定样本数据中获取多元回归函数，并输出计算过程中的关键信息以供查验，本方法侧重回归函数实现，普通界面，内有模块调用实例，简单易学，方便自用。如果感觉好，谢谢支持！
(Stepwise regression the calculation source: Get multiple regression function from the given sample data and output during the calculation of the critical information for inspection, the methods focus on the regression function, common interface, with module calls instance, is easy to learn, easy-occupied. If it feels good, Thank you for your support!)