vvalen: The Van Valen test for equal covariance matrices
In dprep: Data Pre-Processing and Visualization Functions for Classification

Description Usage Arguments Value Author(s) References See Also Examples

The Van Valen nonparametric test for homocedasticity (equal covariance matrices).

1	vvalen(data)

data

The name of the dataset to be tested

Gives the p-value for a Kruskal Wallis test. A p-value near to zero indicates homocedasticity.

Edgar Acuna

Van Valen, L. (1962). A study of fluctuating asymmetry. Evolution Vol. 16, pp. 125142.

mardia

1
2
3

#---------Testing homocedasticity-----
data(colon)
vvalen(colon)

Warning messages:
1: In rgl.init(initValue, onlyNULL) : RGL: unable to open X11 display
2: 'rgl_init' failed, running with rgl.useNULL = TRUE 
3: .onUnload failed in unloadNamespace() for 'rgl', details:
  call: fun(...)
  error: object 'rgl_quit' not found 

	Kruskal-Wallis rank sum test

data:  testlist
Kruskal-Wallis chi-squared = 4.2424, df = 1, p-value = 0.03943