Question

For a 12 pair of observations it was found that $\sum x=30,\sum y=5,\sum x^2=670,\sum y^2=285,\sum xy=334$. Find correlation coefficient.

• A. $0.69$
• B. $0.77$
• C. $0.784$
• D. $0.7$

Answer 1

The correct option is C $0.784$

$n=12$

$\sum x=30,\sum x^2=670,\sum xy=334$ $\sum y=5,\sum y^2=285$

$r=\frac{n\sum xy-(\sum x\times \sum y)}{\sqrt{(n\sum x^2-\sum x^2)(n\sum y^2-\sum y^2)}}=\frac{12\times 334-30\times 5}{\sqrt{(12\times 670-{30}^2)(12\times 285-5^2)}}=0.784$