Sxx Variance Formula -

[ \mathrmVar(\hat\beta 1) = \frac\sigma^2S xx ]

[ \mathrmVar(S_xx) = 2(n-1)\sigma_x^4 ] The variance of the slope estimator (\hat\beta_1) in simple linear regression is: sxx variance formula

It measures the total corrected sum of squares for the predictor variable (x). If (x_i) are fixed constants (standard regression assumption), (S_xx) is not a random variable — it has no variance; it’s just a constant. [ \mathrmVar(\hat\beta 1) = \frac\sigma^2S xx ] [

[ \fracS_xx\sigma_x^2 \sim \chi^2_(n-1) ] sxx variance formula