Question

A company that develops credit score models would like to examine the relationship between the age and credit score of an individual. The accompanying table shows the credit scores and ages of 10 randomly selected people. Determine the sample correlation coefficient between a person's age and credit score.

Please help, I keep getting r=0.648 and it tells me I'm incorrect.

	Age	Credit Score	Age	Credit Score
	35	675	46	790
	23	645	34	730
	54	760	60	750
	28	625	39	675
	30	670	41	620

Answer 1

First we need to calculate pearsons co efficient r:

Count	x	y	xy	x2	y2
1	35	675	23625	1225	455625
2	23	645	14835	529	416025
3	54	760	41040	2916	577600
4	28	625	17500	784	390625
5	30	670	20100	900	448900
6	46	790	36340	2116	624100
7	34	730	24820	1156	532900
8	60	750	45000	3600	562500
9	39	675	26325	1521	455625
10	41	620	25420	1681	384400
Total	390	6940	275005	16428	4848300

From the above data:

Sum (x) = 390,Sum (y) = 6940, Sum (xy) = 275005,

Sum (x)² = 16428, (Sum x)² = (390)² = 152100,

Sum (y)² = 4848300, (Sum y)² = (6940)² = 48163600,

Sum (x) * Sum (y) = 390 * 6940 = 2706600

n = 10

Substituting these values in the equation for r, we get

Therefore r = 0.6966244 0.697 (Rounding to 3 decimal places)