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 p.value < 0.1.
method
the character string "Shapiro-Wilk normality test".
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) and found at http://lib.stat.cmu.edu/apstat/R94.
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
Patrick Royston (1982)
An extension of Shapiro and Wilk's $W$ test for normality to large
samples.
Applied Statistics, 31, 115--124.
Patrick Royston (1982)
Algorithm AS 181: The $W$ test for Normality.
Applied Statistics, 31, 176--180.
Patrick Royston (1995)
Remark AS R94: A remark on Algorithm AS 181: The $W$ test for normality.
Applied Statistics, 44, 547--551.
See Also
qqnorm for producing a normal quantile-quantile plot.