Sxx Variance Formula | Direct

import numpy as np x = np.array([2,4,6,8]) Sxx = np.sum((x - np.mean(x))**2) print(Sxx) # 20.0

, we artificially "inflate" the result slightly to give a more accurate estimate of the true population variance. Variance vs. Standard Deviation Sxx Variance Formula

Because $S_xx$ is the denominator, it represents the spread of your x-values. If $S_xx$ is small (x-values are clustered tightly), the slope becomes very sensitive to changes. If $S_xx$ is large (x-values are spread out), the slope estimate is more stable. import numpy as np x = np