| shapiro.test {stats} | R Documentation |
Shapiro-Wilk Normality Test
Description
Performs the Shapiro-Wilk test of normality.
Usage
shapiro.test(x)
Arguments
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 "htest" containing the following components:
statistic |
the value of the Shapiro-Wilk statistic. |
p.value |
an approximate p-value for the test. This is
said in Royston (1995) to be adequate for |
method |
the character string |
data.name |
a character string giving the name(s) of the data. |
Source
The algorithm used is a C translation of the Fortran code described in
Royston (1995).
The calculation of the p value is exact for n = 3, otherwise
approximations are used, separately for 4 \le n \le 11 and
n \ge 12.
References
Royston JP (1982).
“An Extension of Shapiro and Wilk’s W Test for Normality to Large Samples.”
Applied Statistics, 31(2), 115.
doi:10.2307/2347973.
Royston JP (1982).
“Algorithm AS 181: The W Test for Normality.”
Applied Statistics, 31(2), 176.
doi:10.2307/2347986.
Royston P (1995).
“Remark AS R94: A Remark on Algorithm AS 181: The W-test for Normality.”
Applied Statistics, 44(4), 547.
doi:10.2307/2986146.
See Also
qqnorm for producing a normal quantile-quantile plot.
Examples
shapiro.test(rnorm(100, mean = 5, sd = 3))
shapiro.test(runif(100, min = 2, max = 4))