check_normality.simres, for plotting feature

Author: strengejacke

NAMESPACE

@@ -72,6 +72,7 @@ S3method(check_normality,htest)
 S3method(check_normality,lmerModLmerTest)
 S3method(check_normality,merMod)
 S3method(check_normality,numeric)
+S3method(check_normality,performance_simres)
 S3method(check_outliers,BFBayesFactor)
 S3method(check_outliers,DHARMa)
 S3method(check_outliers,character)

R/check_normality.R

@@ -92,6 +92,23 @@ check_normality.glm <- function(x, ...) {
   invisible(out)
 }
 
+# simulated residuals ----------
+
+#' @export
+check_normality.performance_simres <- function(x, ...) {
+  # check for normality of residuals
+  res <- stats::residuals(x, quantile_function = stats::qnorm)
+  p.val <- .check_normality(res[!is.infinite(res) & !is.na(res)], x)
+
+  attr(p.val, "data") <- x
+  attr(p.val, "object_name") <- insight::safe_deparse_symbol(substitute(x))
+  attr(p.val, "effects") <- "fixed"
+  class(p.val) <- unique(c("check_normality", "see_check_normality", class(p.val)))
+
+  p.val
+}
+
+
 # numeric -------------------
 
 #' @export

tests/testthat/test-check_normality.R

@@ -82,3 +82,34 @@ test_that("check_normality | t-test", {
     ignore_attr = TRUE
   )
 })
+
+
+test_that("check_normality | simulated residuals", {
+  skip_if_not_installed("DHARMa")
+  m <- lm(mpg ~ wt + cyl + gear + disp, data = mtcars)
+  res <- simulate_residuals(m)
+  out <- check_normality(res)
+  expect_equal(
+    as.numeric(out),
+    0.2969038,
+    tolerance = 1e-3,
+    ignore_attr = TRUE
+  )
+  expect_identical(
+    capture.output(print(out)),
+    "OK: residuals appear as normally distributed (p = 0.297)."
+  )
+
+  m <- lm(mpg ~ wt + cyl + gear + disp, data = mtcars)
+  out <- check_normality(m)
+  expect_equal(
+    as.numeric(out),
+    0.2303071,
+    tolerance = 1e-3,
+    ignore_attr = TRUE
+  )
+  expect_identical(
+    capture.output(print(out)),
+    "OK: residuals appear as normally distributed (p = 0.230)."
+  )
+})