Sxx Variance Formula -

If (S_xx) is random (random (x)), the of (\hat\beta 1) involves the expectation of (1/S xx). But conditionally on (x), (S_xx) is constant. 5. Small-Sample Correction If (\sigma_x^2) is unknown, replace with (\hat\sigma x^2 = S xx/(n-1)):

[ \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

If (x_i \sim \texti.i.d. N(\mu_x, \sigma_x^2)): If (S_xx) is random (random (x)), the of

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