Calculate AUC for the ROC in R

Question

I'm quite new to R and I was wondering how can i achieve following thing: I have two vectors (of the same length), one contains sensitivity (tpr) values and the other corresponding 1-specificity (fpr) values. I would like to create a ROC curve and calculate area under curve. Is there some simple way of doing that? I tried to use auc function from the AUC package, but when using auc(tpr, fpr) i get an error: Error in auc(tpr, fpr) : object 'ans' not found.

Answer 1

If you have TPR and FPR you can calculate the area under the curve using a trapezoidal approximation. This can be calculated in R using the trapz function.

By plotting TPR vs FPR you will be able to visualise the curve. Perhaps start with this.