Question

Karl Pearson's coefficient of correlation between x and y for the following data is

x :	3	4	8	9	6	2	1
y :	5	3	7	7	6	9	2

• A. 0.480
• B. – 0.480
• C. 0.408
• D. – 0.408

Answer 1

Answer: (C)

0.408

Answer 2

x	Y	xy	x2	y2
3	5	15	09	25
4	3	12	16	09
8	7	56	64	49
9	7	63	81	49
6	6	36	36	36
2	9	18	04	81
1	2	02	01	04
Σx = 33	$\Sigma y ^ { 2 } = 253$

Now, $r = \frac { \Sigma x y - \frac { \Sigma x \cdot \Sigma y } { n } } { \sqrt { \left\{ \Sigma x ^ { 2 } - \frac { ( \Sigma x ) ^ { 2 } } { n } \right\} \left\{ \Sigma y ^ { 2 } - \frac { ( \Sigma y ) ^ { 2 } } { n } \right\} } }$

⇒ $r = 0.408$.