# test du chi 2 de la semaine der
testchi2 = function() {
	pop = rep(c("F","D"),c(4000,6000))
	ech1 = sample(pop,1000)
	ech2 = sample(pop,1000)
	tab = rbind(table(ech1),table(ech2))
 	test = chisq.test(tab)
	test
}