Re: [R] An issue regarding to gradient

2011-10-11 Thread David Winsemius
On Oct 11, 2011, at 6:02 AM, luke1022 wrote: The following code will get me a curve plot: cutoff <- seq(1,7,0.25) Sensitivity <- 1 - pnorm(cutoff, 5, 0.8) Specificity <- pnorm(cutoff, 3, 1.2) plot(1-Specificity,Sensitivity,main = "ROC curve",type = "o") How do I get a gradient of a particular

[R] An issue regarding to gradient

2011-10-11 Thread luke1022
The following code will get me a curve plot: cutoff <- seq(1,7,0.25) Sensitivity <- 1 - pnorm(cutoff, 5, 0.8) Specificity <- pnorm(cutoff, 3, 1.2) plot(1-Specificity,Sensitivity,main = "ROC curve",type = "o") How do I get a gradient of a particular point on that curve? Any packages/functions allow