swilk: Shapiro-Wilk normality test

In R4VN: Health Data Analysis and Publication-Ready Reporting

Shapiro-Wilk normality test

Description

Runs Shapiro-Wilk tests overall, for many variables, and/or within hierarchical groups. Each tested subgroup must have enough complete observations for the Shapiro-Wilk procedure.

Usage

swilk(x = NULL,
  vars = NULL,
  by = NULL,
  data = NULL,
  digits = 4,
  p_digits = 3,
  show = TRUE,
  console = FALSE)

Arguments

x	One numeric variable; may be omitted when vars is supplied.
vars	Optional vars(...) selection of several numeric variables.
by	Optional hierarchical grouping specification. The final variable in vars(...) is the innermost group and preceding variables are strata.
data	Data frame; active R4VN data is used when omitted.
digits, p_digits	Formatting digits.
show, console	R4VN display controls.

Value

An R4VN result object, invisibly.

See Also

normtest, varform

Examples

d <- data.frame(x = rnorm(40), y = rnorm(40), group = rep(c("A", "B"), each = 20))
swilk(x, data = d)
swilk(vars = vars(x, y), data = d)
swilk(vars = vars(x, y), by = vars(group), data = d)

R4VN documentation built on Sept. 30, 2026, 5:13 p.m.