Kendall tau rank correlations for all pairs of data series
pair	tau	p-value
tau( totaal , metaal )	0.139944453057607	0.166061251688615
tau( totaal , machines )	0.309402799855506	0.00218897384707284
tau( totaal , elektr.app )	0.396847515990088	8.64496406791648e-05
tau( metaal , machines )	0.0203609461874138	0.840105558058857
tau( metaal , elektr.app )	0.138953233987958	0.168901689629664
tau( machines , elektr.app )	0.260185296718687	0.00996290417970336