12.4 Given the following triplets of rankings of six objects:

X 1 3 5 6 4 2 Y 1 2 6 4 3 5 Z 2 1 5 4 6 3

(a) Calculate the Kendall coefficient of partial correlation between X and Y from (12.6.1) and test for independence.

(b) Calculate (12.6.2) for these same data to verify that it is an equivalent expression.