| % File src/library/stats/man/shapiro.test.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2018 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{shapiro.test} |
| \alias{shapiro.test} |
| \title{Shapiro-Wilk Normality Test} |
| \description{ |
| Performs the Shapiro-Wilk test of normality. |
| } |
| \usage{ |
| shapiro.test(x) |
| } |
| \arguments{ |
| \item{x}{a numeric vector of data values. Missing values are allowed, |
| but the number of non-missing values must be between 3 and 5000.} |
| } |
| \value{ |
| A list with class \code{"htest"} containing the following components: |
| \item{statistic}{the value of the Shapiro-Wilk statistic.} |
| \item{p.value}{an approximate p-value for the test. This is |
| said in Royston (1995) to be adequate for \code{p.value < 0.1}.} |
| \item{method}{the character string \code{"Shapiro-Wilk normality test"}.} |
| \item{data.name}{a character string giving the name(s) of the data.} |
| } |
| \references{ |
| Patrick Royston (1982). |
| An extension of Shapiro and Wilk's \eqn{W} test for normality to large |
| samples. |
| \emph{Applied Statistics}, \bold{31}, 115--124. |
| \doi{10.2307/2347973}. |
| |
| Patrick Royston (1982). |
| Algorithm AS 181: The \eqn{W} test for Normality. |
| \emph{Applied Statistics}, \bold{31}, 176--180. |
| \doi{10.2307/2347986}. |
| |
| Patrick Royston (1995). |
| Remark AS R94: A remark on Algorithm AS 181: The \eqn{W} test for |
| normality. |
| \emph{Applied Statistics}, \bold{44}, 547--551. |
| \doi{10.2307/2986146}. |
| } |
| \source{ |
| The algorithm used is a C translation of the Fortran code described in |
| Royston (1995). % and was found at \url{http://lib.stat.cmu.edu/apstat/R94}. |
| The calculation of the p value is exact for \eqn{n = 3}, otherwise |
| approximations are used, separately for \eqn{4 \le n \le 11} and |
| \eqn{n \ge 12}. |
| } |
| \seealso{ |
| \code{\link{qqnorm}} for producing a normal quantile-quantile plot. |
| } |
| % FIXME: could use something more interesting here |
| \examples{ |
| shapiro.test(rnorm(100, mean = 5, sd = 3)) |
| shapiro.test(runif(100, min = 2, max = 4)) |
| } |
| \keyword{htest} |