R/z_test.R

In xanthematthijssen/mypackage: First package for testing package development workflow

#' calculates z-statistic
#'
#' @param v numeric vector
#' @param mu number
#'
#' @return number
#' @export
#'
#' @examples
#' z_test(rnorm(50))
#' z_test(rnorm(50), 1)
#'
z_test <- function(v, mu = 0){
  z <- sum(v- mu) / std_err(v)
  p_value <-  2*pnorm(-abs(z))

  cat(
    "z = ",
    round(z, digits = 4),
    "; p =",
    round(p_value, digits = 4),
    "\nThe sample mean of",
    round(mean(v), digits = 2),
    "is",
    ifelse(p_value < 0.05, "significantly",
           "not significantly"),
    "\ndifferent from ",
    mu
  )

}