Consider the regression model $Y_i = eta X_i + u_i$ Where $u_i$ and $X_i$ satisfy the assumptions specified here. Let $ar{eta}$ denote an estimator of $eta$ that is constructed as $ar{eta} = frac{ar{Y}}{ar{X}}$, where $ar{Y}$ and $ar{X}$ are the sample means of $Y_i$ and $X_i$, respectively. Show that $ar{eta}$ is a linear function of $Y_1, Y_2, ..., Y_n$ $ar{eta} = frac{ar{Y}}{ar{X}} = frac{1}{n} frac{(Y_1 + Y_2 + ... + Y_n)}{ar{X}}$ Show that $ar{eta}$ is conditionally unbiased. 1. $E(Y_i | X_1, X_2, ..., X_n) = eta X_i$ 2. $E(ar{eta} | X_1, X_2, ..., X_n) = E left[ frac{1}{n} frac{(Y_1 + Y_2 + ... + Y_n)}{ar{X}} ight] | (X_1, X_2, ..., X_n) = frac{eta ar{X}}{ar{X}} = eta$
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Now, let's show that β̂ is a linear function of Y. We can rewrite β̂ as β̂ = Y / X - YÌ„ / X + YÌ„ / XÌ„ = (1 / X) * Y - (1 / X) * YÌ„ + (1 / XÌ„) * YÌ„. Since (1 / X) and (1 / XÌ„) are constants, we can rewrite β̂ as β̂ = (1 / X) * Y + (1 / XÌ„) * YÌ„ Show more…
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