Morpho (version 2.2)

permudist: performs permutation testing for group differences.

Description

This function compares the distance between two groupmeans to the distances obtained by random assignment of observations to this groups.

Usage

permudist(data, groups, rounds = 1000, which = NULL)

Arguments

data

array or matrix containing data

groups

factors determining grouping.

rounds

number of permutations

which

integer (optional): in case the factor levels are > 2 this determins which factorlevels to use

Value

• dist
  distance matrix with distances between actual group means
• p.value
  distance matrix containing pairwise p-values obtained by comparing the actual distance to randomly acquired distances

Examples

data(boneData)
proc <- procSym(boneLM)
groups <- name2factor(boneLM,which=3)
perm <- permudist(proc$PCscores[,1:10], groups=groups, rounds=10000)

## now we concentrate only on sex dimorphism between Europeans
groups <- name2factor(boneLM,which=3:4)
levels(groups)
perm1 <- permudist(proc$PCscores, groups=groups,which=3:4, rounds=10000)