rm(list=ls())  
ex9.2 <- read.table("E:例9-2.txt", head=TRUE, fileEncoding="utf8")  
#未加权  
fit <- lm(ex9.2$逻辑变换~ex9.2$年家庭收入)  
fit$coefficients  
#加权  
fit_wi <- lm(ex9.2$逻辑变换~ex9.2$年家庭收入, weights=ex9.2$权重)  
summary(fit_wi)  









