Thus:
[ \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
Variance of a chi-squared random variable with (k) df is (2k): Thus: [ \mathrmVar(S_xx) = 2(n-1)\sigma_x^4 ] The variance