RVAideMemoire (version 0.9-35)

perm.t.test: Permutational Student's t-test

Description

Perform a permutational Student's t-test.

Usage

perm.t.test(formula, data, alternative = c("two.sided", "less", "greater"),
  paired = FALSE, nperm = 999)

Arguments

formula

a formula of the form a ~ b where a gives the data values and b a factor with 2 levels giving the corresponding groups.

data

an optional data frame containing the variables in the formula formula. By default the variables are taken from environment(formula).

alternative

a character string specifying the alternative hypothesis, must be one of "two.sided" (default), "greater" or "less".

paired

a logical indicating whether you want a paired t-test.

nperm

number of permutations.

Value

• statistic
  test statistics of the parametric test.
• permutations
  number of permutations.
• p.value
  p-value of the permutational test.
• estimate
  the estimated mean or difference in means depending on whether it was a paired or not paired test.
• alternative
  a character string describing the alternative hypothesis.
• method
  a character string indicating what type of t-test was performed.
• data.name
  a character string giving the name(s) of the data.
• null.value
  the specified hypothesized value of the mean difference, always 0.

See Also

t.test

Examples

response <- c(rnorm(5),rnorm(5,2,1))
fact <- gl(2,5,labels=LETTERS[1:2])

# Unpaired test
perm.t.test(response~fact)

# Paired test
perm.t.test(response~fact,paired=TRUE)