wilcoxE.test {PASWR} | R Documentation |
Performs exact one sample and two sample Wilcoxon tests on vectors of data.
wilcoxE.test(x, y = NULL, mu = 0, paired = FALSE, alternative = "two.sided", conf.level = 0.95)
x |
is a numeric vector of data values. Non-finite (i.e. infinite or missing) values will be omitted. |
y |
an optional numeric vector of data values |
mu |
a number specifying an optional parameter used to form the null hypothesis |
paired |
a logical indicating whether you want a paired test |
alternative |
a character string specifying the alternative hypothesis,
must be one of "two.sided" (default), "greater" ,
or "less" . The initial letter only may be given. |
conf.level |
confidence level of the interval |
If only x
is given, or if both x
and y
are given and
paired="TRUE"
, a Wilcoxon signed rank test of the null hypothesis
that the distribution of x
(in the one sample case) or of
x - y
(in the paired two sample case) is symmetric about
mu
is performed.
Otherwise, if both x
and y
are given and paired="FALSE"
,
a Wilcoxon rank sum test is done. In this case, the null
hypothesis is that the distributions of x
and y
differ by a
location shift of mu
and the alternative is that they differ by some other
location shift (and the one-sided alternative "greater"
is that
x
is shifted to the right of y
).
A list with class htest
containing the following components:
statistic |
the value of the test statistic with a name describing it |
p.value |
the p-value for the test |
null.value |
the location parameter mu |
alternative |
a character string describing the alternative hypothesis |
method |
the type of test applied |
data.name |
a character string giving the names of the data |
conf.int |
a confidence interval for the location parameter |
estimate |
an estimate of the location parameter |
The function is rather primitive and should only be used for problems with fewer than 19 observations as the memory requirements are rather large.
Alan T. Arnholt
Gibbons, J.D. and Chakraborti, S. (1992). Nonparametric Statistical Inference. Marcel Dekker Inc., New York.
Myles Hollander & Douglas A. Wolfe (1999), Nonparametric Statistical Inference. New York: John Wiley & Sons.
# Wilcoxon Signed Rank Test - Example 10.3 PH <- c(7.2,7.3,7.3,7.4) wilcoxE.test(PH, mu=7.25, alternative="greater") # Wilcoxon Signed Rank Test (Dependent Samples) - Example 10.5 part c. attach(Aggression) wilcoxE.test(violence,noviolence,paired=TRUE,alternative="greater") detach(Aggression) # Wilcoxon Rank Sum Test - Example 10.7 x <- c(7.2,7.2,7.3,7.3) y <- c(7.3,7.3,7.4,7.4) wilcoxE.test(x,y)