Crème <- read.table("https://husson.github.io/livre_exo/chap6_ex3.csv", header = TRUE, sep=";", encoding = "latin1", stringsAsFactors = TRUE)
Crème[,1] <- as.factor(Crème[,1])
Crème[,2]<-relevel(Crème[,2],"J+5")
t.test(Viscosité ~ Date, data = Crème, var.equal = TRUE)

library(FactoMineR)
AovSum(Viscosité ~ Date, data = Crème)

t.test(Viscosité ~ Date, data = Crème, var.equal = TRUE, paired = TRUE)
AovSum(Viscosité ~ Date + Lot, data = Crème)