dieta<-LETTERS[rep(c(1:3),each=6)]
cor<-rep(c("claro","escuro"),each=3,times=3)
pesos<- c(0.1,1.1,3.7,1.5,-0.1,2.0,5.7,-1.2,-1.5,0.6,-3.0,-0.3,3.0,-0.4,0.6,-0.2,0.3,1.5)
hamsters<-data.frame(dieta,cor,pesos)