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Wilcoxon Rank Sum and Signed Rank Tests

Usage

wilcox.test(x, y = NULL, alternative = "two.sided", mu = 0, 
            paired = FALSE, exact = FALSE, correct = TRUE)

Arguments

x numeric vector of data values.
y an optional numeric vector of data values.
alternative indicates the alternative hypothesis and must be one of "two.sided", "greater" or "less". You can specify just the initial letter.
mu a number specifying an optional location parameter.
paired a logical indicating whether you want a paired test.
exact a logical indicating whether an exact p-value should be computed.
correct a logical indicating whether to apply continuity correction in the normal approximation for the p-value.

Description

wilcox.test performs one and two sample Wilcoxon tests on vectors of data.

If only x is given, or if both x and y are given and paired is TRUE, a Wilcoxon signed rank test of the null that the median of x (in the one sample case) or of x-y (in the paired two sample case) equals mu is performed.

Otherwise, if both x and y are given and paired is FALSE, a Wilcoxon rank sum test (equivalent to the Mann-Whitney test) is carried out. In this case, the null hypothesis is that the location of the distributions of x and y differ by mu.

Value

A list with class "htest" containing the following components:
statistic the value of the test statistic with a name describing it.
parameter the parameter(s) for the exact distribution of the test statistic. Currently, only normal approximations are used.
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.