The table shows several values of x and their corresponding values of y. Which of the following is closest to the correlation between x and y?
Understand the Problem
The question is asking for the correlation coefficient between the given values of x and y from the provided table. This involves understanding how to calculate or identify the degree of relationship between the two sets of numbers.
Answer
The correlation coefficient is \(0.98\).
Answer for screen readers
The correlation coefficient (r) is approximately (0.98).
Steps to Solve
- Calculate the means of x and y
The mean of (x) is calculated as: $$ \bar{x} = \frac{1 + 2 + 3 + 4 + 5}{5} = \frac{15}{5} = 3 $$
The mean of (y) is calculated as: $$ \bar{y} = \frac{3 + 4 + 7 + 8 + 12}{5} = \frac{34}{5} = 6.8 $$
- Compute the deviations from the mean
For each value of (x) and (y), calculate the deviation from their respective means:
- For (x): (x_i - \bar{x})
- For (y): (y_i - \bar{y})
- Calculate the products of the deviations
Calculate: $$ d_{xy} = \sum (x_i - \bar{x})(y_i - \bar{y}) $$
- Compute the squares of the deviations
Calculate: $$ d_{x} = \sum (x_i - \bar{x})^2 $$
And for (y): $$ d_{y} = \sum (y_i - \bar{y})^2 $$
- Calculate the correlation coefficient
The correlation coefficient (r) is given by: $$ r = \frac{d_{xy}}{\sqrt{d_{x} \cdot d_{y}}} $$
- Choose the answer closest to the calculated coefficient
Find the value of (r) and compare it with the options A through E to determine which is the closest.
The correlation coefficient (r) is approximately (0.98).
More Information
The correlation coefficient measures the strength and direction of a linear relationship between two variables. A value close to (1) indicates a strong positive correlation, while a value close to (-1) indicates a strong negative correlation.
Tips
- Miscalculating the means of (x) and (y).
- Forgetting to square deviations in computing (d_{x}) and (d_{y}).
- Incorrectly applying the correlation formula.
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