#
# Confidence intervals for the sere; multiply the sere value by these
#
sereci <- function(sere, n, m, p=.95) {
    q <- (1-p)/2
    df <- n*(m-1)
    x <- sere^2 *df
    
    excess <- x- df
    if (excess > 0) {
        tfun <- function(non, x, q) 
            pchisq(x, df, ncp=non) -q
        lfit <- uniroot(tfun, c(0, excess), q=1-q, x=x)
        ufit <- uniroot(tfun, c(1,2)*excess, q=q, x=x)
        sqrt(1 + c(lfit$root, ufit$root) / df)
    }
    else c(0,0)
}