setwd("D:\\Rdownload\\lianxi\\third") #设定工作路径
d3.5<-read.csv("ex3.5.csv",header=T) #将ex3.5.csv数据读入到d3.5中
glm.logit<-glm(admit~gre+gpa+rank,family=binomial(link =logit),data=d3.5) #建立admit关于gre,gpa,rank的logistic回归模型,数据为d3.5
summary(glm.logit) #模型汇总
##
## Call:
## glm(formula = admit ~ gre + gpa + rank, family = binomial(link = logit),
## data = d3.5)
##
## Coefficients:
## Estimate Std. Error z value Pr(>|z|)
## (Intercept) -3.449548 1.132846 -3.045 0.00233 **
## gre 0.002294 0.001092 2.101 0.03564 *
## gpa 0.777014 0.327484 2.373 0.01766 *
## rank -0.560031 0.127137 -4.405 1.06e-05 ***
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## (Dispersion parameter for binomial family taken to be 1)
##
## Null deviance: 499.98 on 399 degrees of freedom
## Residual deviance: 459.44 on 396 degrees of freedom
## AIC: 467.44
##
## Number of Fisher Scoring iterations: 4
##容易看出,该回归模型的回归系数都很显著,gre和gpa的回归系数在5%的水平上显著;rank的回归系数在0.1%的水平上显著。
##于是可以得到lnˆp/1-ˆp = - 3.4495 + 0.0023gre + 0.7770gpa - 0.5600rank