pp.bootcor <- function (x, trials=1e4, confidence=.95) { orig <- cor(x)[1,2] boot <- numeric(trials) nr <- nrow(x) for(i in 1:trials) { boot[i] <- cor(x[sample(nr, nr, replace=TRUE),])[1,2] } alpha <- (1 - confidence) / 2 c(orig, quantile(boot, c(alpha, 1-alpha))) }