Determine Rank Correlation Coefficient
A group of 8 accountancy students are tested in Quantitative Techniques and Law II. Their rankings in the two tests were as:
|
Student
|
Q.T. ranking
|
Law II ranking
|
d
|
d2
|
|
A
|
2
|
3
|
-1
|
1
|
|
B
|
7
|
6
|
1
|
1
|
|
C
|
6
|
4
|
2
|
4
|
|
D
|
1
|
2
|
-1
|
1
|
|
E
|
4
|
5
|
-1
|
1
|
|
F
|
3
|
1
|
2
|
4
|
|
G
|
5
|
8
|
-3
|
9
|
|
H
|
8
|
7
|
1
|
1
|
Σd2 = 22
d = Q. T. ranking - Law II ranking
R = 1 - {(6Σd2)/(n(n2 -1))}
1 -{(6(22))/(8(82 -1))} = 0.74
Hence we conclude that there is a reasonable agreement among student's performances in the two types of tests.
NOTE: in this illustration, if we are given the actual marks then we find r. R varies between -1 and +1.