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)