b: Zhang and Mueller’s [1] measure of decision bias
[1] Zhang, J., and Mueller, S. T. (2005). A note on roc analysis and non-parametric estimate of sensitivity. Psychometrika, 70, 145-154.
Calculates metric based on hit, miss, correct rejection, and false alarm counts
Calculates metric based on hit rate and false alarm rate
based on the number of args and the availability of .prob routes call to appropriate method.