Also see function rocdemo.sca in the ROC package.
The area under the 45 degree line in an ROC curve has an area of 0.5.
Regards, Adai
On Tue, 2005-08-02 at 09:24 -0400, Ravi Varadhan wrote:
Hi,
To find the area lying between the curve y = y(x) and 45 degree line (which,
assuming it goes
Question on graphs:
The default case for drawing a graph in R, is where a little space is left
on the x and y axis before the first tick i.e. even if I say xlim=c(0,1) --
there will be some space between the edge of the x-axis and where 0 is
placed. If I want 0 on the edge, how do I do it in
On Tue, 2005-08-02 at 18:20 +0530, Renuka Sane wrote:
Question on graphs:
The default case for drawing a graph in R, is where a little space is left
on the x and y axis before the first tick i.e. even if I say xlim=c(0,1) --
there will be some space between the edge of the x-axis and where
Le 02.08.2005 14:50, Renuka Sane a écrit :
Question on graphs:
The default case for drawing a graph in R, is where a little space is left
on the x and y axis before the first tick i.e. even if I say xlim=c(0,1) --
there will be some space between the edge of the x-axis and where 0 is
placed.
How about:
trapz = function(x, y)
{ # computes the integral of y with respect to x using trapezoidal
integration.
idx = 2:length(x)
return (as.double( (x[idx] - x[idx-1]) %*% (y[idx] + y[idx-1])) / 2)
}
Jarek
\===
Jarek Tuszynski,
Hi,
To find the area lying between the curve y = y(x) and 45 degree line (which,
assuming it goes through the origin, is y = x), you can use the following
function based on trapezoidal rule:
trap.rule - function(x,f) {sum(diff(x)*(f[-1]+f[-length(f)]))/2}
trap.rule(x,f=y-x)
This area will be
