在1stopt1.5(破解版)中运行下列程序,结果回归系数全部为0,请问这是为什么呢?谢谢~
代码:
Title "The Scale of Cities";
//Parameters a(1:9);//a1,a2,a3,a4,a5,a6,a7,a8,a9;
//Variable y,x(3);//x1,x2,x3;
Function y=a1*x1+a2*x1^2+a3*x1^3+a4*x1*x2+a5*x1^2*x2+a6*x1^3*x2+a7*x1*x3+a8*x1^2*x3+a9*x1^3*x3;
Data;
y x1 x2 x3
(数据区)