You may use any notes, lectures, or your textbook. Do not work with anyone else on this assessment.
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\[\textrm{var}(\epsilon')=\sigma^2\mathbf{I}\]
Minimize \((y - \mathbf{X}\beta)^T\Sigma^{-1}(y-\mathbf{X}\beta)\) with respect to \(\beta\) to calculate the estimate for \(\hat\beta\)
Using the estimate for \(\hat\beta\) that you previously calculated, take the expectation of \(\hat\beta\). Is this an unbiased estimate for \(\beta\)?
Show that
\[\textrm{var}(\hat\beta)=(\mathbf{X}^T\Sigma^{-1}\mathbf{X})^{-1}\sigma^2\]