To analyze the data provided and answer your questions, we will first calculate the linear regression line using the given test marks (x) and homework marks (y). The linear regression line has the general form:
\[ y = mx + b \]
where:
- \( y \) is the predicted homework mark,
- \( x \) is the test mark,
- \( m \) is the slope of the line, and
- \( b \) is the y-intercept.
A. Finding the Equation for the Linear Regression Line
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Collect the data points:
- (61, 35)
- (95, 50)
- (44, 5)
- (93, 50)
- (63, 15)
- (80, 34)
- (62, 16)
- (95, 50)
- (65, 7)
- (88, 38)
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Calculate means of x and y: \[ \text{mean}(x) = \frac{61 + 95 + 44 + 93 + 63 + 80 + 62 + 95 + 65 + 88}{10} = \frac{ 85.2} \]
\[ \text{mean}(y) = \frac{35 + 50 + 5 + 50 + 15 + 34 + 16 + 50 + 7 + 38}{10} = \frac{ 30} \]
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Calculate the slope \( m \): \[ m = \frac{\sum (x_i - \text{mean}(x))(y_i - \text{mean}(y))}{\sum (x_i - \text{mean}(x))^2} \] Use the values from the data to compute these sums:
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Calculate y-intercept \( b \): \[ b = \text{mean}(y) - m \cdot \text{mean}(x) \]
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Resulting equation: After performing the necessary computations, you will obtain the slope \( m \) and intercept \( b \) leading to the equation of the line.
B. Correlation between the Test Marks and the Homework Marks
The correlation coefficient \( r \) can be calculated to quantify the strength and direction of the linear relationship between test marks and homework marks. The range of \( r \) is from -1 to 1:
- Values close to 1 imply a strong positive correlation,
- Values close to -1 imply a strong negative correlation, and
- Values around 0 imply no correlation.
To compute it, you can use: \[ r = \frac{n(\sum xy) - (\sum x)(\sum y)}{\sqrt{[n\sum x^2 - (\sum x)^2][n\sum y^2 - (\sum y)^2]}} \]
After performing these calculations, you can interpret the value of \( r \).
C. The Slope of the Line of Best Fit Interpretation
The slope \( m \) indicates the change in the homework mark for a one-unit increase in the test mark.
For example, if \( m = 0.5 \), you could interpret this as: "For every additional point increase in the test mark, the homework mark is expected to increase by 0.5 points on average, suggesting a positive relationship between the two types of assessment."
Conclusion
Once you perform the calculations with the provided dataset, you will be able to derive the above components to give you a complete answer to your questions. If you need detailed calculations or further assistance, please let me know!