出现下列情况是怎么回事???处理数据 一直都是这种状况
LDependent Variable: PURCHASE
Method: ML - Binary Logit (Quadratic hill climbing)
Date: 12/23/07 Time: 03:37
Sample: 1 566
Included observations: 566
Convergence achieved after 5 iterations
WARNING: Singular covariance - coefficients are not unique
Covariance matrix computed using second derivatives
Variable Coefficient Std. Error z-Statistic Prob.
结果显示 变量系数 有数据 标准差 ,z统计检验都显示NA, 我核查数据很多变了,没有问题,究竟怎么回事???
着急,谢谢