R/t_results.R

In zief0002/educate: Miscellaneous R Functions for Educational Statistics

#' Print t-Test Results
#'
#' @param x t.test() or t_test() object
#'
#' @return Printed output of the t-test results including test type, hypotheses, t-value, df, and p-value.
#' @export
#'
#' @examples
#' my_t = t.test(cars$speed, mu = 16, alternative = "less")
#' t_results(my_t)
#'
t_results = function(x){

  inequality_sign = switch(x$alternative, "less"="<", "greater"=">", "two.sided"="≠")

  if (x$method == "One Sample t-test"){
    cat(
      "\n", rep("-", 50), "\n", x$method, "\n", rep("-", 50), "\n",
      "\nH[0]: mu = ", x$null.value,
      "\nH[A]: mu ", inequality_sign, " ", x$null.value,
      "\n\nt(", x$parameter, ") = ", x$statistic,
      "\np = ", x$p.value,
      "\n\n", rep("-", 50), "\n",
      sep = "")
  } else{
    # Extract group names
    group1 = gsub(x = names(x$estimate)[1], pattern = "mean in group ", replacement = "")
    group2 = gsub(x = names(x$estimate)[2], pattern = "mean in group ", replacement = "")

    cat(
      "\n", rep("-", 50), "\n", x$method, "\n", rep("-", 50), "\n",
      "\nH[0]: mu_[", group1, "] = mu_[", group2, "]",
      "\nH[A]: mu_[", group1, "] ", inequality_sign, " mu_[", group2, "]",
      "\n\nt(", x$parameter, ") = ", x$statistic,
      "\np = ", x$p.value,
      "\n\n", rep("-", 50), "\n",
      sep = "")
    }
}