R/permTest.formula.R

In CarletonStats: Functions for Statistics Classes at Carleton College

#' @describeIn permTest Permutation test
#' @export

permTest.formula <-
function(formula, data = parent.frame(), subset,...)
{ if (missing(formula) || (length(formula) != 3L) || (length(attr(terms(formula[-2L]),
        "term.labels")) != 1L))
        stop("'formula' missing or incorrect")
    m <- match.call(expand.dots = FALSE)
    if (is.matrix(eval(m$data, parent.frame())))
        m$data <- as.data.frame(data)
    m[[1L]] <- as.name("model.frame")
    m$... <- NULL
    mf <- eval(m, parent.frame())

    nmiss <- length(attr(mf, "na.action"))
    if (nmiss > 0)
     cat("\n ", nmiss, "observations removed due to missing values.\n")

    response <- attr(attr(mf, "terms"), "response")
    x <- mf[[response]]
    g <- mf[[-response]]

    y <- do.call("permTest", c(list(x, g), ...))

    y
}