Table 8 Spearman rank coefficients between costs measures (*if p < 0.05)

Cost A

1

Cost B

0.9841*

1

Cost C

0.9710*

0.9878*

1

Cost D

0.5176*

0.5442*

0.5632*

1

Cost E

0.3824*

0.4164*

0.4180*

0.6453*

1

Ratio A

0.7752*

0.7525*

0.7370*

0.3120*

0.2467*

1

Ratio B

0.7786*

0.7843*

0.7699*

0.3501*

0.2910*

0.9800*

1

Ratio C

0.7767*

0.7813*

0.7872*

0.3680*

0.2913*

0.9726*

0.9888*

1

Ratio D

0.4142*

0.4337*

0.4483*

0.8397*

0.5433*

0.5357*

0.5606*

0.5737*

Ratio E

0.3319*

0.3601*

0.3608*

0.5349*

0.9099*

0.4197*

0.4583*

0.4568*