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(d) (5 points) Using the linear combination of independent univariate normals result (posted as a hint below homework 1pdf file), find thedistributionof the least squares estimator ofβfound in part (1b) - including the mean and variance.Confirm that your variance expression matches that obtained in part (1c).(e) (5 points) Using 120A/B expectation results in the case of the model above, show thatW=∑ni=1Yi∑ni=1xiis another unbiased estimator ofβ.(f) (5 points) Using 120A/B variance results in the case of the model above, calculate the variance ofWin part (1e), andcompare it to the variance of the ordinary least squares estimator found in part (1b).Hint: If it helps you in this problem, you may assume thatnXj=1x2j≥(∑ni=1xi)2n!.22