from random import normalvariate

def moyenne(L):
    s=0
    for k in L:
        s=s+k
    return s/len(L)

def simule_loi_normale(n,mu,sigma):
    L=[]
    for k in range(n):
        L.append(normalvariate(mu, sigma))
    return L

def serie_moyennes(N,n,mu,sigma):
    S=[]
    for k in range(N):
        L=simule_loi_normale(n,mu,sigma)
        S.append(moyenne(L))
    return S