How to plot ROC curve ?

I work about database include 60 person and i have a result as follow : 58 identify and 2 not identify. i.e Rec rate=96.667 I ask about : 1- how to calculate tpr and fpr?.....i calculated it as tpr=58/60=0.967 and fpr=0 (is this method right?). 2- how to plot ROC curve? Note: I have only positive set= 60 person and i haven't negative set. Thanks in advance

Answer 1

[Image Analyst]

You don't need negatives for the ROC curve. You just need positives, and you have them both. You call them tpr and fpr. Of course since your false positive rate is 0 and doesn't vary at all, your ROC curve would be just a horizontal line going from (0, .967) to (1, .967) This good performance won't last as you begin to encounter more challenging situations. It sounds like your test set was identical to your training set so of course the ROC curve will be a very high flat line.