Permutation test for paired data.

Usage

permTestPaired(x, ...)

# Default S3 method
permTestPaired(
  x,
  y,
  B = 9999,
  alternative = "two.sided",
  plot.hist = TRUE,
  plot.qq = FALSE,
  x.name = deparse(substitute(x)),
  y.name = deparse(substitute(y)),
  xlab = NULL,
  ylab = NULL,
  title = NULL,
  seed = NULL,
  ...
)

# S3 method for class 'formula'
permTestPaired(formula, data, subset, ...)

Arguments

x: a numeric vector.
...: further arguments to be passed to or from methods.
y: a numeric vector.
B: the number of resamples.
alternative: the alternative hypothesis. Options are "two.sided", "less" and "greater".
plot.hist: a logical value. If TRUE, create a histogram displaying the permutation distribution of the statistic.
plot.qq: a logical value. If TRUE, include a quantile-normal plot of the permuation distribution.
x.name: Label for x variable
y.name: Label for y variable
xlab: an optional character string for the x-axis label
ylab: an optional character string for the y-axis label
title: an optional character string giving the plot title
seed: optional argument to set.seed
formula: a formula of the form y ~ x, where x, y are both numeric variables.
data: an optional data frame containing the variables in the formula. By default the variables are taken from environment(formula).
subset: an optional vector specifying a subset of observations to be used.

Value

Returns invisibly a vector of the replicates of the test statistic (ex. mean of the difference of the resampled variables).

Details

For two paired numeric variables with n rows, randomly select k of the n rows (k also is randm) and switch the entries \(latex\) and then compute the mean of the difference of the two variables (y-x).

Observations with missing values are removed.

Methods (by class)

permTestPaired(default): Permutation test for paired data.
permTestPaired(formula): Permutation test for paired data.

References

Tim Hesterberg's website: https://www.timhesterberg.net/bootstrap-and-resampling

Author

Laura Chihara

Examples


#Does chocolate ice cream have more calories than vanilla ice cream, on average?
#H0: mean number of calories is the same
#HA: mean number of calories is greater in chocolate ice cream

permTestPaired(Icecream$VanillaCalories, Icecream$ChocCalories, alternative = "less")
#> 
#> 	** Permutation test **
#> 
#>  Permutation test with alternative: less 
#>  Observed mean
#>   Icecream$VanillaCalories :  191.4103 	 Icecream$ChocCalories :  198.7436 
#>  Observed difference: 7.33333 
#> 
#>  Mean of permutation distribution: -0.02095 
#>  Standard error of permutation distribution: 2.3687 
#>  P-value:  0.9994 
#> 
#> 	*-------------*
#> 

permTestPaired(ChocCalories ~ VanillaCalories, data = Icecream, alternative = "greater")
#> 
#> 	** Permutation test **
#> 
#>  Permutation test with alternative: greater 
#>  Observed mean
#>   VanillaCalories :  191.4103 	 ChocCalories :  198.7436 
#>  Observed difference: 7.33333 
#> 
#>  Mean of permutation distribution: 0.00606 
#>  Standard error of permutation distribution: 2.34752 
#>  P-value:  0.0003 
#> 
#> 	*-------------*
#>