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
d
d2
P
92
1
67
5
-4
16
Q
82
3
88
2
4
R
60
5(5.5)
58
7(7.5)
-2
S
87
80
0
T
72
69
U
77
-2.50
6.25
V
52
8
0.5
0.25
W
50
9
6
X
47
10
32
Y
59
7
54
Σd^{2} = 43.5
∴ Rank correlation r = 1 - {(6Σd^{2})/ (n (n^{2} -1))}
= 1 - {(6(43.5))/(10(10^{2} -1))}
= 1 - (261/990)
= 0.74 as High positive correlation among mathematics marks and accounts