Bessel's Correction in Variance Calculation

import numpy as np

data = [10, 12, 23, 23, 16, 23, 21, 16]

# Population Variance (N)
pop_var = np.var(data)

# Sample Variance (N-1) - The "Unbiased" Estimator
sample_var = np.var(data, ddof=1)

Why it matters: For small samples, dividing by N underestimates the population variance. ddof=1 keeps statistical reporting honest.