ميزات البرنامج · تباين العينة بطريقة ويلفورد

from math import isfinite
def sample_variance(values):
    if type(values) not in (list, tuple) or not 2 <= len(values) <= 10000:
        raise ValueError("sample count")
    if any(type(x) not in (int, float) or not -1e150 <= x <= 1e150
           or not isfinite(x) for x in values):
        raise ValueError("bounded finite samples")
    mean, m2 = 0.0, 0.0
    for n, x in enumerate(values, 1):
        delta = x - mean
        mean += delta / n
        m2 += delta * (x - mean)
    return m2 / (len(values) - 1)