Questions: HW 4.2: Least-Squares Regression Line Question 2 of 7 (1 point) I Question Attempt: 1 of Unlimited Compute the least-squares regression equation for the given data set. Round the slope and y-intercept to at least four decimal places x 6 3 1 4 5 y 5 3 2 7 1 Regression line equation: ŷ

HW 4.2: Least-Squares Regression Line
Question 2 of 7 (1 point) I Question Attempt: 1 of Unlimited

Compute the least-squares regression equation for the given data set. Round the slope and y-intercept to at least four decimal places

x 6 3 1 4 5
y 5 3 2 7 1

Regression line equation: ŷ
Transcript text: HW 4.2: Least-Squares Regression Line Question 2 of 7 (1 point) I Question Attempt: 1 of Unlimited Compute the least-squares regression equation for the given data set. Round the slope and $y$-intercept to at least four decimal places \begin{tabular}{l|lllll} $x$ & 6 & 3 & 1 & 4 & 5 \\ \hline$y$ & 5 & 3 & 2 & 7 & 1 \end{tabular} Regression line equation: $\hat{y}$
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Solution

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Solution Steps

To compute the least-squares regression line for the given data set, we need to determine the slope (m) and y-intercept (b) of the line that best fits the data points. This involves calculating the means of the x and y values, the covariance of x and y, and the variance of x. The slope is the covariance divided by the variance, and the y-intercept is calculated using the means and the slope.

Step 1: Calculate the Means of \(x\) and \(y\)

To find the least-squares regression line, we first calculate the means of the \(x\) and \(y\) values. The mean of \(x\) is given by:

\[ \bar{x} = \frac{6 + 3 + 1 + 4 + 5}{5} = 3.8 \]

Similarly, the mean of \(y\) is:

\[ \bar{y} = \frac{5 + 3 + 2 + 7 + 1}{5} = 3.6 \]

Step 2: Calculate the Covariance and Variance

Next, we calculate the covariance of \(x\) and \(y\) and the variance of \(x\). The covariance is calculated as:

\[ \text{cov}(x, y) = \sum (x_i - \bar{x})(y_i - \bar{y}) = 5.6 \]

The variance of \(x\) is:

\[ \text{var}(x) = \sum (x_i - \bar{x})^2 = 14.8 \]

Step 3: Calculate the Slope (\(m\)) and Y-Intercept (\(b\))

The slope \(m\) of the regression line is the covariance divided by the variance:

\[ m = \frac{\text{cov}(x, y)}{\text{var}(x)} = \frac{5.6}{14.8} \approx 0.3784 \]

The y-intercept \(b\) is calculated using the means and the slope:

\[ b = \bar{y} - m \cdot \bar{x} = 3.6 - 0.3784 \cdot 3.8 \approx 2.1622 \]

Final Answer

\(\boxed{\hat{y} = 0.3784x + 2.1622}\)

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