source("http://www.uvm.edu/~rsingle/stat5210/data/scripts-5210.R")

 dat <- bookdata("ch05q02.txt")
 head(dat)
 
 y.x1 <- lm(SBP~QUET, data=dat)
 summary(y.x1)
 anova(y.x1)

 y.x2 <- lm(SBP~AGE, data=dat)
 summary(y.x2)
 anova(y.x2)
 
 y.x1x2 <- lm(SBP~QUET+AGE, data=dat)
 summary(y.x1x2)
 anova(y.x1x2)