Kendall tau rank correlations for all pairs of data series
pair	tau	p-value
tau( a , b )	0.833181049684188	0
tau( a , c )	0.884603728906709	0
tau( a , d )	0.760836330421892	0
tau( b , c )	0.829816876525868	0
tau( b , d )	0.838716060195362	0
tau( c , d )	0.862359408232899	0