代码如下
data$Exam_fedu_level<-as.factor(data$Exam_fedu_level)
data$Exam_year<-as.factor(data$Exam_year)
data$Exam_year<-relevel(data$Exam_year,ref="2016")
data$Exam_fbmi<-as.factor(data$Exam_fbmi)
data$Exam_fjob<-as.factor(data$Exam_fjob)
MEE.Age<-function(data)
  require(mfx)
  require(Hmisc)
  require(margins)
  data$Exam_fbmi<-droplevels(impute(data$Exam_fbmi,median))
  data$Exam_fjob<-droplevels(impute(data$Exam_fjob,median))
  data$Exam_fedu_level<-droplevels(impute(data$Exam_fedu_level,median))

  for(i in ncol(data):1) if(nlevels(data[,i])==1) data<-data[,-i]

  age.glm<-glm(formula=paste("Exam_fage~Exam_year+",paste(names(data)[3:ncol(data)],collapse="+"),sep=""),family=gaussian(),data=data)
出现错误：Error in `contrasts<-`(`*tmp*`, value = contr.funs[1 + isOF[nn]]) :