[R] no true negative data, need roc curve

[Jessica Streicher]

To clarify:

Is TN = 0 or do you not know TN (N)?

On 16.08.2012, at 11:51, vjyns wrote:

> Hi,
> 
>   I want to plot ROC curve for my detection algorithm which detects
> features in different images at two different thresholds.
> 
> 6 different images used and obtained tp, fp and fn. No tn in my case.
> 
> in first threshold run i obtained 6 values of tp,fp and fn. In second
> threshold run agian i got 6 more.
> 
> i had calculated tpr and fpr. How to plot ROC in this case. 
> 
> Is this possible to plot ROC curve in this case? If s, please guide me to
> plot that.
> 
> thank you.
> 
> http://r.789695.n4.nabble.com/file/n4640474/in1.png 
> 
> 
> 
> --
> View this message in context: http://r.789695.n4.nabble.com/no-true-negative-data-need-roc-curve-tp4640474.html
> Sent from the R help mailing list archive at Nabble.com.
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.