def indicateurs(L):
    n = len(L)
    m = 0
    for x in L:
        m = m + x
    m = m / n
    s = 0
    for x in L:
        s = s + (x - m) ** 2
    s = (s / n) ** 0.5
    k = 0
    for x in L:
        if m - 2 * s <= x <= m + 2 * s:
            k = k + 1
    return m, s, k / n