Question

Determine the value of the coefficient of correlation, r, for the following data.

X 4 6 7 11 16 17 21

Y 18 13 13 8 7 7 5

(Round the intermediate values to 3 decimal places. Round your answer to 3 decimal places.)

r= ?

Answer 1

Solution:

X	Y	XY	X^2	Y^2
4	18	72	16	324
6	13	78	36	169
7	13	91	49	169
11	8	88	121	64
16	7	112	256	49
17	7	119	289	49
21	5	105	441	25

n	7
sum(XY)	665.00
sum(X)	82.00
sum(Y)	71.00
sum(X^2)	1208.00
sum(Y^2)	849.00
Numerator	-1167.00
Denominator	1249.91
r	-0.9337
r square	0.8717
Xbar(mean)	11.7143
Ybar(mean)	10.1429
SD(X)	4.9469
SD(Y)	4.0415
b	-0.6738
a	18.0358

r = -0.934