Page 2 - Home assignment-correlation analysis.
P. 2
Physics: 35, 23, 47, 17, 10, 43, 9, 6, 28
Mathematics: 30, 33, 45, 23, 8, 49, 12, 4, 31
Compute the student’s ranks in the two subjects and compute the
Spearman rank correlation.
Solution:- Calculation of Spearman’s rank coefficient of correlation.
Let the marks scored by the students be X and mathematics be Y.
2
X Y = −
35 30 3 5 -2 4
23 33 5 3 2 4
47 45 1 2 -1 1
17 23 6 6 0 0
10 08 7 8 -1 1
43 49 2 1 1 1
09 12 8 7 1 1
06 04 9 9 0 0
28 31 4 4 0 0
2
n=9 =12
6× 2
= 1 − −
3
6×12
= 1 − 9 −9
3
72 1
= 1 − = 1 − = 0.9
720 10
There exists a very high degree of positive correlation between marks
scored by the students in physics and mathematics.
In case of equal ranks, we apply the formula: -
3 − 2 − 3
3
3
− 1
2
6×( + 1 + 2 + 3 +⋯………….).
12
= 1 − 12 − 12
3
