Problem

For the following table of data, a. Draw a scatterplot. b. Calculate the correlation coefficient. c. Calculate the least squares line and \begin{tabular}{|c|c|c|c|c|c|c|c|c|c|c|} \hline $\mathbf{x}$ & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 & 10 \\ \hline $\mathbf{y}$ & 0.1 & 0.7 & 1.1 & 2.1 & 2.9 & 3.1 & 3.1 & 4.4 & 4.6 & 5.1 \\ \hline \end{tabular} graph it on the scatterplot. d. Predict the $y$-value when $x$ is 11 . a. Choose the correct answer below. A. B. C. D. b. Calculate the correlation coefficient. 11 (Do not round until the final answer. Then round to the nearest thousandth as needed.)

Solution

Step 1 :Given the data points, we have the following values: \(x = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]\) and \(y = [0.1, 0.7, 1.1, 2.1, 2.9, 3.1, 3.1, 4.4, 4.6, 5.1]\).

Step 2 :The number of pairs of data, denoted as \(n\), is 10.

Step 3 :The sum of the x-values, denoted as \(\sum x\), is 55.

Step 4 :The sum of the y-values, denoted as \(\sum y\), is approximately 27.2.

Step 5 :The sum of the product of the x and y values, denoted as \(\sum xy\), is 195.6.

Step 6 :The sum of the squares of the x-values, denoted as \(\sum x^2\), is 385.

Step 7 :The sum of the squares of the y-values, denoted as \(\sum y^2\), is approximately 100.28.

Step 8 :Substitute these values into the formula for the correlation coefficient, \(r = \frac{n(\sum xy) - (\sum x)(\sum y)}{\sqrt{[n\sum x^2 - (\sum x)^2][n\sum y^2 - (\sum y)^2]}}\).

Step 9 :After calculating, we find that the correlation coefficient, \(r\), is approximately 0.987611212433532.

Step 10 :Rounding to the nearest thousandth, the final answer is \(\boxed{0.988}\).

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Source: https://solvelyapp.com/problems/16441/

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