Download retinol data
> retinol=read.csv2("C:/Users/ke05/Documents/My Dropbox/Biostat course/EPHD 312/Spring 2017/Project 1/TPretinol.csv")
> retinol$tabac<-factor(tabac, levels=c(1,2,3), labels=c("Never", "Ex", "Current"))
# Plot weight by group and color by group
library("ggpubr")
> ggboxplot(retinol, x = "tabac", y = "age", color = "tabac", palette = c("#00AFBB", "#E7B800", "#FC4E07"), order = c("Never", "Ex", "Current"), ylab = "age", xlab = "Smoking Status")
#using the library {car}
> boxplot (retdiet~tabac, xlab="smoking status", ylab="concentration", data=retinol)
