R help - Jul 2013 - LDA and confidence ellipse

Hi,

I wish to add confidence ellipse on my LDA result of the iris data set.
Therefore:
Is there statistical logic to do that as I only wish it to make the species
separation more visable?
How can I add it to the script below  (ggplot): 
require(MASS)
require(ggplot2)
iris.lda<-lda(Species ~ Sepal.Length + Sepal.Width + Petal.Length +
Petal.Width,  data = iris)
LD1<-predict(iris.lda)$x[,1]
LD2<-predict(iris.lda)$x[,2]
ggplot(iris, aes(x=LD1, y=LD2, col=iris$Species) ) + geom_point( size = 4,
aes(color = iris$Species))+theme_bw()   

Could someone please help me. Thank you very much.



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Hi,
May be this helps:
require(MASS)
require(ggplot2)
iris.lda<-lda(Species ~ Sepal.Length + Sepal.Width + Petal.Length +
Petal.Width,? data = iris)
datPred<-data.frame(Species=predict(iris.lda)$class,predict(iris.lda)$x)

library(ellipse)
dat_ell <- data.frame()
for(g in levels(datPred$Species)){
dat_ell <- rbind(dat_ell,
cbind(as.data.frame(with(datPred[datPred$Species==g,], ellipse(cor(LD1, LD2),
???????????????????????????????????????? scale=c(sd(LD1),sd(LD2)), 
????????????????????????????????????????
centre=c(mean(LD1),mean(LD2))))),Species=g))
}

ggplot(datPred, aes(x=LD1, y=LD2, col=Species) ) + geom_point( size = 4,
aes(color =
Species))+theme_bw()+geom_path(data=dat_ell,aes(x=x,y=y,color=Species),size=1,linetype=2)?


A.K.


Hi, 

I wish to add confidence ellipse on my LDA result of the iris data set. 
Therefore: 
Is there statistical logic to do that as I only wish it to make the species
separation more visable?
How can I add it to the script below ?(ggplot): 
require(MASS) 
require(ggplot2) 
iris.lda<-lda(Species ~ Sepal.Length + Sepal.Width + Petal.Length +
Petal.Width, ?data = iris)
LD1<-predict(iris.lda)$x[,1] 
LD2<-predict(iris.lda)$x[,2] 
ggplot(iris, aes(x=LD1, y=LD2, col=iris$Species) ) + geom_point( size = 4,
aes(color = iris$Species))+theme_bw() ?

Could someone please help me. Thank you very much.