Illustration of Rank Correlation Coefficient
Sometimes numerical data such refers to the quantifiable variables may be described after which a rank correlation coefficient may be worked out.
Is such a condition, the rank correlation coefficient will be determined after the described variables have been converted into ranks. See the given illustration:
|
Candidates
|
Math
|
r
|
Accounts
|
r
|
d
|
d2
|
|
P
|
92
|
1
|
67
|
5
|
-4
|
16
|
|
Q
|
82
|
3
|
88
|
1
|
2
|
4
|
|
R
|
60
|
5(5.5)
|
58
|
7(7.5)
|
-2
|
4
|
|
S
|
87
|
2
|
80
|
2
|
0
|
0
|
|
T
|
72
|
4
|
69
|
4
|
0
|
0
|
|
U
|
60
|
5(5.5)
|
77
|
3
|
-2.50
|
6.25
|
|
V
|
52
|
8
|
58
|
7(7.5)
|
0.5
|
0.25
|
|
W
|
50
|
9
|
60
|
6
|
3
|
9
|
|
X
|
47
|
10
|
32
|
10
|
0
|
0
|
|
Y
|
59
|
7
|
54
|
9
|
-2
|
4
|
|
|
|
|
|
|
|
Σd2 = 43.5
|
∴ Rank correlation r = 1 - {(6Σd2)/ (n (n2 -1))}
= 1 - {(6(43.5))/(10(102 -1))}
= 1 - (261/990)
= 0.74 as High positive correlation among mathematics marks and accounts