def variance(x):
""" assumes x has at least two elements """
n = len(x)
deviations = de_mean(x)
return alg.sum_of_squares(deviations) / (n - 1)
def variance(x):
""" assumes x has at least two elements """
n = len(x)
deviations = de_mean(x)
return alg.sum_of_squares(deviations) / (n - 1)