在Python中准确计算方差

Question

我正在计算包含许多子列表的列表

A

的方差。然而，输出与数学计算不同。这是为什么？我介绍当前和预期的输出。

import statistics

A = [[2], [7], [3], [12], [9]]

# Flatten the sublists to get a single list of values
flattened_values = [value for sublist in A for value in sublist]

# Calculate the variance using the statistics module
variance_value = statistics.variance(flattened_values)

print("Variance:", variance_value)

当前输出为

Variance: 17.3

预期输出是

13.84

Answer 1

只使用numpy？

import numpy as np

A = [[2], [7], [3], [12], [9]]

flattened_values = [value for sublist in A for value in sublist]

print("Variance:", np.var(A))