from math import sqrt

def moyenne(x1, x2, x3, x4, x5):
    m = (x1 + x2 + x3 + x4 + x5) / 5
    return m

def ecart(x1, x2, x3, x4, x5):
    m = moyenne(x1, x2, x3, x4, x5)
    v = ((x1 - m)**2 + (x2 - m)**2 + (x3 - m)**2 + (x4 - m)**2 + (x5 - m)**2) / 5
    e = sqrt(v)
    return e