Dummy Regression

dd <- mtcars

names(dd)
table(dd$cyl)

dd$c1 <- 0
dd$c1[dd$cyl==4] <- 1

dd$c2 <- 0
dd$c2[dd$cyl==6] <- 1

dd$c3 <- 0
dd$c3[dd$cyl==8] <- 1

res <- lm(mpg ~ wt + cyl, data = dd)
res

res2 <- lm(mpg ~ wt + c1 + c2, data = dd)
res2

res3 <- lm(mpg ~ wt + c2 + c3, data = dd)
res3