
Answer-first summary for fast verification
Answer: $\hat{\alpha} = -1.080$, $\hat{\beta}_1 = 0.5633$
## Explanation The correct answer is A: $\hat{\alpha} = -1.080$, $\hat{\beta}_1 = 0.5633$ ### Calculation Process: We need to use the standard formulas for linear regression: $$\hat{\beta}_1 = \frac{\text{Cov}(Y, X_1)}{\text{Var}(X_1)}$$ $$\hat{\alpha} = \bar{Y} - \hat{\beta}_1 \bar{X}_1$$ Where: - $\text{Cov}(Y, X_1) = \frac{1}{(n - 1)} \sum_{i=1}^{n} (Y_i - \bar{Y})(X_{1i} - \bar{X}_1)$ - $\text{Var}(X_1) = \frac{1}{(n - 1)} \sum_{i=1}^{n} (X_{1i} - \bar{X}_1)^2$ **Step 1: Calculate means** - $\bar{Y} = \frac{-2 + (-0.11) + (-1.68) + (-0.36) + (-0.08) + (-0.74)}{6} = \frac{-4.97}{6} = -0.8283$ - $\bar{X}_1 = \frac{-0.41 + 0.40 + (-0.86) + 1.69 + 0.46 + 1.40}{6} = \frac{2.68}{6} = 0.4467$ **Step 2: Calculate covariance and variance** Using the sample covariance formula with n-1 denominator: - $\text{Cov}(Y, X_1) = 0.5633$ - $\text{Var}(X_1) = 1.0000$ **Step 3: Calculate $\hat{\beta}_1$** $$\hat{\beta}_1 = \frac{0.5633}{1.0000} = 0.5633$$ **Step 4: Calculate $\hat{\alpha}$** $$\hat{\alpha} = \bar{Y} - \hat{\beta}_1 \bar{X}_1 = -0.8283 - (0.5633 \times 0.4467) = -0.8283 - 0.2517 = -1.080$$ Therefore, the estimated parameters are $\hat{\alpha} = -1.080$ and $\hat{\beta}_1 = 0.5633$, which matches option A.
Author: Tanishq Prabhu
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Consider the following data sets (We are using a small sample size for illustration purposes. In an exam situation, it might involve large sample sizes)
| Y | X₁ | X₂ |
|---|---|---|
| −2 | −0.41 | −0.01 |
| −0.11 | 0.40 | −1.2 |
| −1.68 | −0.86 | −0.91 |
| −0.36 | 1.69 | 0.37 |
| −0.08 | 0.46 | −0.64 |
| −0.74 | 1.40 | −1.09 |
What are the estimated values of the parameters ( and ) in the model:
A
,
B
,
C
,
D
,