Package 'R2sample'

Title: Various Methods for the Two Sample Problem
Description: The routine twosample_test() in this package runs the two sample test using various test statistic. The p values are found via permutation or large sample theory. The routine twosample_power() allows the calculation of the power in various cases, and plot_power() draws the corresponding power graphs. The routine run.studies allows a user to quickly study the power of a new method and how it compares to some of the standard ones.
Authors: Wolfgang Rolke [aut, cre] (ORCID: <https://orcid.org/0000-0002-3514-726X>)
Maintainer: Wolfgang Rolke <[email protected]>
License: GPL (>= 2)
Version: 5.0.0
Built: 2026-10-06 12:31:33 UTC
Source: https://github.com/cran/R2sample

Help Index


This function finds the p values of several tests based on large sample theory

Description

This function finds the p values of several tests based on large sample theory

Usage

asymptotic_pvalues(x, n, m)

Arguments

x

a vector of test statistics

n

size of sample 1

m

size of sample 2

Value

A vector of p values.


Create case studies

Description

This function creates the functions needed to run the various case studies. That means it generates two data sets the are equal with respect to three out of these four: mean, variance, skewness and kurtosis, and differ in the other. If which_diff=mixed, all are different.

Usage

case_studies(
  which,
  which_diff = "mean",
  data_type = "cont",
  n = 500,
  nbins = 50,
  funs_list,
  ReturnCaseNames = FALSE
)

Arguments

which

name of the case study.

which_diff

="mean", name of parameter in which data sets differ.

data_type

="cont", is data continuous or discrete?

n

=500, sample sizes.

nbins

=50, number of bins for discrete data

funs_list

list of alternative functions

ReturnCaseNames

=FALSE, should list of case studies be returned?

Value

a function that generates data sets


This function runs the chi-square test for continuous or discrete data

Description

This function runs the chi-square test for continuous or discrete data

Usage

chi_power(
  rxy,
  alpha = 0.05,
  B = 1000,
  xparam,
  yparam,
  nbins = c(50, 10),
  minexpcount = 5,
  typeTS
)

Arguments

rxy

a function to generate data

alpha

=0.05 type I error probability of test

B

=1000 number of simulation runs

xparam

vector of parameter values

yparam

vector of parameter values

nbins

=c(50, 10) number of desired bins

minexpcount

=5 smallest number of counts required in each bin

typeTS

type of problem, continuous/discrete, with/without weights

Value

A matrix of power values


funs_list

Description

function definitions for case studies

Usage

funs_list

Format

'funs_list'

A list of functions


New test for continuous data

Description

This function runs a test for continuous data

Usage

myTS_cont(x, y, TSextra)

Arguments

x

first data set

y

second data set

TSextra

list with extra info

Value

a number


This function runs a test for discrete data

Description

This function runs a test for discrete data

Usage

myTS_disc(x, y, vals, TSextra)

Arguments

x

counts for first data set

y

counts for second data set

vals

values of discrete data

TSextra

list with extra info

Value

a number


a local function needed for the vignette

Description

a local function needed for the vignette

Usage

myTS2(x, y, vals)

Arguments

x

An integer vector.

y

An integer vector.

vals

A numeric vector with the values of the discrete rv.

Value

A vector with test statistics


param

Description

list of matrices with parameter values for case studies

Usage

param

Format

'param'

A list of matrices with numbers


This function draws the power graph, with curves sorted by the mean power and smoothed for easier reading.

Description

This function draws the power graph, with curves sorted by the mean power and smoothed for easier reading.

Usage

plot_power(pwr, xname = " ", title = " ", Smooth = TRUE, span = 0.25)

Arguments

pwr

a matrix of power values, usually from the twosample_power command

xname

Name of variable on x axis

title

(Optional) title of graph

Smooth

=TRUE lines are smoothed for easier reading

span

=0.25bandwidth of smoothing method

Value

plt, an object of class ggplot.


Power for tests with p values

Description

This function estimates the power of test routines that calculate p value(s)

Usage

power_newtest(TS, f, xparam, yparam, TSextra, alpha = 0.05, B = 1000)

Arguments

TS

routine to calculate test statistics.

f

routine that generates data.

xparam

values of first parameter under the alternative hypothesis.

yparam

values of second parameter under the alternative hypothesis.

TSextra

list passed to TS.

alpha

=0.05 type I error.

B

= 1000 number of simulation runs to estimate the power.

Value

A matrix of power values


power_study

Description

the results of the included power studies

Usage

power_study

Format

'power_study'

A list of matrices with powers


Find the power of two sample tests using Rcpp and parallel computing.

Description

Find the power of two sample tests using Rcpp and parallel computing.

Usage

powerR(
  rxy,
  xparam,
  yparam,
  TS,
  typeTS,
  TSextra,
  alpha = 0.05,
  B = 1000,
  SuppressMessages,
  maxProcessor
)

Arguments

rxy

function to generate a list with data sets x, y and (optional) vals, weights

xparam

first argument passed to rxy

yparam

second argument passed to rxy

TS

test statistic

typeTS

which format has TS?

TSextra

list of items passed TS

alpha

=0.05, the level of the hypothesis test

B

= 1000 number of simulation runs

SuppressMessages

= FALSE print informative messages?

maxProcessor

maximum number of cores to use. If maxProcessor=1 no parallel computing is used.

Value

A numeric vector of power values.


pvaluecdf

Description

data to draw a graph in vignette

Usage

pvaluecdf

Format

'pvaluecdf'

A matrix


Runs the shiny app associated with R2sample package

Description

Runs the shiny app associated with R2sample package

Usage

run_shiny()

Value

No return value, called for side effect of opening a shiny app


Power Comparisons

Description

This function runs the case studies included in the package and compares the power of a new test to those included.

Usage

run.studies(
  studies = 1:40,
  types = 1:5,
  data_type = "cont",
  TS,
  TSextra,
  With.p.value = FALSE,
  n = 500,
  alpha = 0.05,
  B = 1000,
  SuppressMessages = TRUE
)

Arguments

studies

=1:40, either the names of the studies, or their numbers. If missing all the studies are run.

types

=1:5, either the types of studies, or their numbers. If missing all types are run.

data_type

="cont", continuous or discrete data

TS

routine to calculate test statistics.

TSextra

list passed to TS.

With.p.value

=FALSE does user supplied routine return p values?

n

= 500, desired sample size.

alpha

=0.05 type I error

B

= 1000

SuppressMessages

= TRUE

Details

For details consult vignette("R2sample","R2sample")

Value

A matrix of power values.

Examples

TSextra=list(nbins=5, statistic=FALSE) # Use 5 bins and calculate p values
run.studies(1:2, 1:2, TS=myTS_cont, TSextra=TSextra, With.p.value=TRUE, B=100)

This function does some rounding to nice numbers

Description

This function does some rounding to nice numbers

Usage

signif_digits(x, d = 4)

Arguments

x

a list of two vectors

d

=4 number of digits to round to

Value

A list with rounded vectors


test function

Description

test function

Usage

timecheck(dta, TS, typeTS, TSextra)

Arguments

dta

data set

TS

test statistics

typeTS

format of TS

TSextra

additional info TS

Value

Mean computation time


Power estimation for two-sample methods

Description

Find the power of various two sample tests using Rcpp and parallel computing.

Usage

twosample_power(
  f,
  ...,
  TS,
  TSextra,
  With.p.value = FALSE,
  alpha = 0.05,
  B = 1000,
  nbins = c(50, 10),
  minexpcount = 5,
  UseLargeSample,
  samplingmethod = "Binomial",
  rnull,
  SuppressMessages = FALSE,
  maxProcessor
)

Arguments

f

function to generate a list with data sets x, y and (optional) vals, weights

...

additional arguments passed to f, up to 2

TS

routine to calculate test statistics for non-chi-square tests

TSextra

additional info passed to TS, if necessary

With.p.value

=FALSE does user supplied routine return p values?

alpha

=0.05, the level of the hypothesis test

B

=1000, number of simulation runs.

nbins

=c(50,10), number of bins for chi large and chi small.

minexpcount

=5 minimum required count for chi square tests

UseLargeSample

should p values be found via large sample theory if n,m>10000?

samplingmethod

="Binomial" or independence in discrete data case

rnull

a function that generates data from a model, possibly with parameter estimation.

SuppressMessages

= FALSE print informative messages?

maxProcessor

maximum number of cores to use. If maxProcessor=1 no parallel computing is used.

Details

For details consult vignette("R2sample","R2sample")

This routine runs a number of different two-sample tests for univariate data, either discrete or continuous. The user can also provide their own test method.

Value

A numeric vector of power values.

Examples

# Power of standard normal vs. normal with mean mu.
 f1=function(mu) list(x=rnorm(25), y=rnorm(25, mu))
 #Power of uniform discrete distribution vs. with different probabilities.
 twosample_power(f1, mu=c(0,2), B=100, maxProcessor = 1)
 f2=function(n, p) list(x=table(sample(1:5, size=1000, replace=TRUE)), 
       y=table(sample(1:5, size=n, replace=TRUE, 
       prob=c(1, 1, 1, 1, p))), vals=1:5)
 twosample_power(f2, n=c(1000, 2000), p=c(1, 1.5), B=100, maxProcessor = 1)
 # Compare power of a new test with those in package:
 myTS=function(x,y) {z=c(mean(x)-mean(y),sd(x)-sd(y));names(z)=c("M","S");z}
 cbind(twosample_power(f1, mu=c(0,2), TS=myTS,B=100, maxProcessor = 1),
       twosample_power(f1, mu=c(0,2), B=100, maxProcessor = 1))
 # Power estimation if routine returns a p value, using two parameters for 
 #  the alternative
 f3=function(mu, n) list(x=rnorm(25), y=rnorm(n, mu))
 myTS2=function(x, y) {out=ks.test(x,y)$p.value; names(out)="KSp"; out}      
 twosample_power(f3, c(0,1), c(25, 30), TS=myTS2, With.p.value = TRUE,  B=100)

Tests for the univariate two-sample problem

Description

This function runs a number of two sample tests using Rcpp and parallel computing.

Usage

twosample_test(
  x,
  y,
  vals = NA,
  TS,
  TSextra,
  wx = rep(1, length(x)),
  wy = rep(1, length(y)),
  B = 5000,
  nbins = c(50, 10),
  minexpcount = 5,
  maxProcessor,
  UseLargeSample,
  samplingmethod = "Binomial",
  rnull,
  SuppressMessages = FALSE,
  doMethods = "all"
)

Arguments

x

a vector of numbers if data is continuous or of counts if data is discrete or a list with the data

y

a vector of numbers if data is continuous or of counts if data is discrete.

vals

=NA, a vector of numbers, the values of a discrete random variable. NA if data is continuous data.

TS

routine to calculate test statistics for non-chi-square tests

TSextra

additional info passed to TS, if necessary

wx

A numeric vector of weights of x.

wy

A numeric vector of weights of y.

B

=5000, number of simulation runs for permutation test

nbins

=c(50,10), number of bins for chi square tests.

minexpcount

=5, minimum required expected counts for chi-square tests.

maxProcessor

maximum number of cores to use. If missing (the default) no parallel processing is used.

UseLargeSample

should p values be found via large sample theory if n,m>10000?

samplingmethod

="Binomial" or "independence" for discrete data

rnull

a function that generates data from a model, possibly with parameter estimation.

SuppressMessages

= FALSE print informative messages?

doMethods

="all" a vector of codes for the methods to include. If "all", all methods are used.

Details

For details consult vignette("R2sample","R2sample")

Value

A list of two numeric vectors, the test statistics and the p values.

Examples

R2sample::twosample_test(rnorm(1000), rt(1000, 4), B=1000)
 myTS=function(x,y) {z=c(mean(x)-mean(y),sd(x)-sd(y));names(z)=c("M","S");z}
 R2sample::twosample_test(rnorm(1000), rt(1000, 4), TS=myTS, B=1000)
 vals=1:5
 x=table(sample(vals, size=100, replace=TRUE))
 y=table(sample(vals, size=100, replace=TRUE, prob=c(1,1,3,1,1)))
 R2sample::twosample_test(x, y, vals)

Adjusted p values for simultaneous testing in the two-sample problem.

Description

This function runs a number of two sample tests using Rcpp and parallel computing and then finds the correct p value for the combined tests.

Usage

twosample_test_adjusted_pvalue(
  x,
  y,
  vals = NA,
  TS,
  TSextra,
  wx = rep(1, length(x)),
  wy = rep(1, length(y)),
  B = c(5000, 1000),
  nbins = c(50, 10),
  minexpcount = 5,
  samplingmethod = "independence",
  rnull,
  SuppressMessages = FALSE,
  doMethods
)

Arguments

x

a vector of numbers if data is continuous or of counts if data is discrete, or a list with the data.

y

a vector of numbers if data is continuous or of counts if data is discrete.

vals

=NA, a vector of numbers, the values of a discrete random variable. NA if data is continuous data.

TS

routine to calculate test statistics for non-chi-square tests

TSextra

additional info passed to TS, if necessary

wx

A numeric vector of weights of x.

wy

A numeric vector of weights of y.

B

=c(5000, 1000), number of simulation runs for permutation test

nbins

=c(50,10), number of bins for chi square tests.

minexpcount

= 5, minimum required expected counts for chi-square tests

samplingmethod

="independence" or "Binomial" for discrete data

rnull

routine for parametric bootstrap

SuppressMessages

= FALSE print informative messages?

doMethods

="all" a vector of codes for the methods to include. If "all", all methods are used.

Details

For details consult vignette("R2sample","R2sample")

Value

A list of two numeric vectors, the test statistics and the p values.

Examples

x=rnorm(100)
 y=rt(200, 4)
 R2sample::twosample_test_adjusted_pvalue(x, y, B=c(500, 500))
 vals=1:5
 x=table(c(1:5, sample(1:5, size=100, replace=TRUE)))-1
 y=table(c(1:5, sample(1:5, size=100, replace=TRUE, prob=c(1,1,3,1,1))))-1
 R2sample::twosample_test_adjusted_pvalue(x, y, vals, B=c(500, 500))