The marks scored by 4 students in Mathematics and Physics are ranked as shown in the table below

Mathematics 3 4 2 1
Physics 4 3 1 2

Calculate the Spearmann's rank correlation coefficient.

A.

0.2

B.

0.5

C.

0.6

D.

0.7

Correct answer is C

Maths (x) Rank \(r_{x}\) Physics (y) Rank \(r_{y}\) \(d = |r_{x} - r_{y}|\) \(d^{2}\)
3 2 4 1 1 1
4 1 3 2 1 1
2 3 1 4 1 1
1 4 2 3 1 1
Total         4

\(\rho = 1 - \frac{6\sum{d^{2}}}{n(n^{2} - 1)}\)

\( 1 - \frac{6 \times 4}{4(4^{2} - 1)} = 1 - \frac{24}{60}\)

= \(1 - 0.4 = 0.6\)