[R] Jonckheere-Terpstra test

[Marie Kraska]

Hello, Can anyone tell me how to write the R script to get the P-value
for the Jonckheere-Terpstra (JT) test? Following is the code I am using.
I cannot get the P-value to print out. Any help would be appreciated.
Thanks. Marie


jt <- function(x, alpha=.05){
        if(is.list(x) == 0) stop("Please enter a list of vectors.")
        k <- length(x)
        us <- matrix(0,k,k)
        for(i in 1:(k-1)){
                for(j in (i+1):k){
                        us[i,j] <- wilcox.test(x[[j]],
x[[i]])$statistic
                }
        }
        sum(us)
}


 con <- c(40,35,38,43,44,41)
 gpb <- c(38,40,47,44,40,42)
 gpc <- c(48,40,45,43,46,44)

 jt(list(con,gpb,gpc))