"Percentile"<- function(x,nboot,theta,...,alpha = c(.025,.05,.1,.9,.95,.975))
{

# Nonparametric percentile bootstrap conf. Int. 
# adapted from bcanon by Mai Zhou 
# no bias correction, no accelaration. Ref. book of Efron and Tibshirani

call <- match.call()
thetahat <- theta(x,...)
bootsam <- t(matrix(sample(x,size=length(x)*nboot,replace=T),ncol=nboot))

thetastar <- apply(bootsam,1,theta,...)
ooo <- trunc(alpha*nboot)                   # Can we improve trunc
confpoints <- sort(thetastar)[ooo]       # so that take linear interpolation
confpoints <- cbind(alpha,confpoints)

dimnames(confpoints)[[2]] <- c("alpha","%tile points")
return(confpoints, call=call)
 
}