[R] calculating area under the ROC curve

[John Christie]

Hi,
	I recently did a study where we gathered decisions and confidence  
ratings.  My understanding is that I can convert this to a ROC curve  
by getting hits and false alarms at the various confidence ratings.   
I figured out that part of the problem.  I noticed a few functions  
for calculating AUC.  Are there any preferred ones for this  
particular kind of design?