Area of density
On 6/09/2008, at 8:32 AM, pragmatic wrote:
Hello! Please, anybody help me. Can I calculate area of density was created by:
D <- density(x)
In other words I want to know area under curve 'plot(D)' and It's good to calculate area before and after 0 separately.
(1) You could use splinefun() foo <- splinefun(D$x,D$y) integrate(foo,min(D$x),0) integrate(foo,0,max(D$x)) or you could use simp() from http://finzi.psych.upenn.edu/R/Rhelp02a/archive/134918.html with(D,simp(y=y[x<0],x=x[x<0])) with(D,simp(y=y[x>0],x=x[x>0])) You'll get different answers, neither of which is ``correct''. cheers, Rolf Turner ###################################################################### Attention:\ This e-mail message is privileged and confid...{{dropped:9}}