Question

Please consider the following values for the variables X and Y. Treat each row as a pair of scores for the variables X and Y (with the first row providing the labels "X" and "Y"). X Y 2 4 4 3 6 5 7 7 11 6 Please calculate Pearson's correlation coefficient (r) for these data and report your answer below. When reporting your answer, please provide three decimal places (if relevant).

Answer 1

Answer:

The Pearson's coefficient of correlation between the is 0.700.

Step-by-step explanation:

The correlation coefficient is a statistical degree that computes the strength of the linear relationship amid the relative movements of the two variables (i.e. dependent and independent).It ranges from -1 to +1.

The formula to compute correlation between two variables X and Y is:

$r(X, Y)=\frac{Cov(X, Y)}{\sqrt{V(X)\cdot V(Y)}}$

The formula to compute covariance is:

$Cov(X, Y)=n\cdot \sum XY-\sum X \cdot\sum Y$

The formula to compute the variances are:

$V(X)=n\cdot\sum X^{2}-(\sum X)^{2}\\V(Y)=n\cdot\sum Y^{2}-(\sum Y)^{2}$

Consider the table attached below.

Compute the covariance as follows:

$Cov(X, Y)=n\cdot \sum XY-\sum X \cdot\sum Y$

                 $=(5\times 165)-(30\times 25)\\=75$

Thus, the covariance is 75.

Compute the variance of X and Y as follows:

$V(X)=n\cdot\sum X^{2}-(\sum X)^{2}\\=(5\times 226)-(30)^{2}\\=230\\\\V(Y)=n\cdot\sum Y^{2}-(\sum Y)^{2}\\=(5\times 135)-(25)^{2}\\=50$

Compute the correlation coefficient as follows:

$r(X, Y)=\frac{Cov(X, Y)}{\sqrt{V(X)\cdot V(Y)}}$

            $=\frac{75}{\sqrt{230\times 50}}$

            $=0.69937\\\approx0.70$

Thus, the Pearson's coefficient of correlation between the is 0.700.