windows()
attach(B)
plot(math~income,xlim=c(0,60))
abline(lm(math~income),col=2,lwd=2)
reg <- lm(math~income)
windows()
plot(reg,1)
windows()
hist(reg$ residuals)
B $ income2 = income*income
attach(B) #attach已過時故要再補attach
reg1 <- lm(read~income + income2)
summary(reg)
summary(reg1)
windows()
plot(reg1,1)
windows()
plot(reg,1)
anova(reg1,reg)
windows()
hist(income,breaks=50)
#B $ ln_income = log(income,base=exp(1))
B $ ln_income = log(income)
attach(B)
windows()
hist(ln_income,breaks=50)
windows()
plot(read~ln_income)
abline(lm(read~ln_income),cl=2,lwd=2)
windows() #####刪掉了
plot(B) #####刪掉了
reg2 <-lm(read~ln_income)
summary(reg2)
summary(reg1)
windows()
plot(read~income)
B$High = ifelse(income >=17,1,0)
head(B,20) #####刪掉了
attach(B)
reg4 <- lm ( read~income+High+High*income)
B$H_income = ifelse(income >=17,income-17,0)
attach(B)
reg5 <- lm ( read~income+H_income)
summary(reg4)
summary(reg5)
anova(reg5)
windows()
plot(B)
