1、Call:glm(formula = flag ~ X1wt + X1tt + X1zf + X1zp + X2wt + X2tt + X2zf + X2zp, family = binomial(), data = datasample)Deviance Residuals: Min 1Q Median 3Q Max -1.938 -1.252 0.774 0.905 1.495 Coefficients: Estimate Std. Error z value Pr(>|z|) (Intercept) 8971.4616 6768.6303 1.325 0.1850 X1wt -2.1824 1.9992 -1.092 0.2750 X1tt -146.9639 113.6175 -1.293 0.1958 X1zf 0.2125 0.3947 0.538 0.5903 X1zp 1728.6228 1318.8870 1.311 0.1900 X2wt 7.6280 3.9075 1.952 0.0509 .X2tt 59.5489 103.7609 0.574 0.5660 X2zf 0.5778 0.4304 1.342 0.1795 X2zp -769.1400 1195.9249 -0.643 0.5201 ---Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1(Dispersion parameter for binomial family taken to be 1) Null deviance: 812.58 on 632 degrees of freedomResidual deviance: 780.10 on 624 degrees of freedomAIC: 798.1Number of Fisher Scoring iterations: 4
2、
Call:glm(formula = flag ~ X1wt, family = binomial(), data = datasample)Deviance Residuals: Min 1Q Median 3Q Max -1.7745 -1.2838 0.8103 0.8906 1.3475 Coefficients: Estimate Std. Error z value Pr(>|z|) (Intercept) -146.626 34.212 -4.286 1.82e-05 ***X1wt 1.119 0.260 4.305 1.67e-05 ***---Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1(Dispersion parameter for binomial family taken to be 1) Null deviance: 812.58 on 632 degrees of freedomResidual deviance: 793.77 on 631 degrees of freedomAIC: 797.77Number of Fisher Scoring iterations: 4
上面第1个输出结果是把所有预测变量放进去建模的输出结果,显示每个变量表现都不显著。而第2个输出模型结果是把X1wt这个变量单独作为预测变量,结果显示预测显著,请问这是什么原因呢?为什么X1wt作为预测变量与其他变量一起建模的时候系数会表现不显著呢?