Pmat: Create a set of permutations.

Description Usage Arguments Details Value Examples

View source: R/public.R

Description

Compute a permutation matrix used as argument in aovperm, lmperm, clusterlm functions. The first column represents the identity permutation.

Usage

1
Pmat(np = 5000, n, type = "default")

Arguments

np

A numeric value for the number of permutations. Default is 5000.

n

A numeric value for the number of observations.

type

A character string to specify the type of matrix. See Details.

Details

type can set to :
"default" : np random with replacement permutations among the n! permutations.
"all" : all n! possible permutations.

Value

A matrix n x np containing the permutations/coinflips. First permutation is the identity.

Examples

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
## data
data("emergencycost")

## Create a set of 2000 permutations
set.seed(42)
pmat = Pmat(np = 2000, n = nrow(emergencycost))

## centrering the covariate to the mean
emergencycost$LOSc <- scale(emergencycost$LOS, scale = FALSE)

## ANCOVA
mod_cost_0 <- aovperm(cost ~ LOSc*sex*insurance, data = emergencycost, np = 2000)
mod_cost_1 <- aovperm(cost ~ LOSc*sex*insurance, data = emergencycost, P = pmat)
mod_cost_2 <- aovperm(cost ~ LOSc*sex*insurance, data = emergencycost, P = pmat)

## Same p-values for both models 1 and 2 but differents of model 0
mod_cost_0
mod_cost_1
mod_cost_2

permuco documentation built on Feb. 14, 2018, 5:04 p.m.